Partition into Unequal Groups - Intermediate Level: tricky scenarios handling Partition into Unequal Groups INTERMEDIATE

This expert challenge 📈 worksheet focuses on Partition into Unequal Groups - a key topic in Permutation Combination. You'll solve 20 intermediate-level problems (Worksheet 5 of 10). The primary focus is on tricky scenarios handling. Master how to solve partition into unequal groups, partition into unequal groups tricks, and partition into unequal groups shortcut methods through systematic practice.

📝 Worksheet 5 of 10 • 20 questions • ⏱️ Estimated time: 20 minutes • 🎯 Intermediate level

What you'll learn in this worksheet:
Your progress through Partition into Unequal Groups
Worksheet 5 of 10 (44% complete)

Question 1

In how many ways can 10 distinct people be divided into 3 groups of sizes 5, 4, 1 (groups are unlabeled but have different sizes)?
Step-by-Step Solution:

Concept: Partitioning into groups of specified sizes. When group sizes are different, groups are automatically distinguishable by size.

Given:
- Total people: 10
- Group sizes: 5, 4, 1
- Groups are unlabeled (no names like Team A, Team B)

Formula:
$$\frac{n!}{n_1! \cdot n_2! \cdot ... \cdot n_k!}$$

Step 1 - Choose first group:
Choose 5 people from 10: C(10, 5) = 252

Step 2 - Choose second group:
From remaining 5 people, choose 4: C(5, 4) = 5

Continue for all groups:
C(10,5) = 252
C(5,4) = 5
C(1,1) = 1 (last group)

Step 3 - Multiply:
Total ways = 252 × 5 × 1 (last group)
= 1260

Simplified formula:
= 10! / (5! × 4! × 1!)
= 3628800 / (120 × 24 × 1)
= 1260

Key Insight: Since groups have different sizes, we don't divide by k! (they're naturally distinguishable by their sizes).

Contrast with equal groups:
- If groups were same size: would divide by k!
- Here, sizes differ: no division needed

Verification: Sum of group sizes = 10 = 10 ✓

Question 2

In how many ways can 10 distinct people be divided into 3 groups of sizes 5, 4, 1 (groups are unlabeled but have different sizes)?
Step-by-Step Solution:

Concept: Partitioning into groups of specified sizes. When group sizes are different, groups are automatically distinguishable by size.

Given:
- Total people: 10
- Group sizes: 5, 4, 1
- Groups are unlabeled (no names like Team A, Team B)

Formula:
$$\frac{n!}{n_1! \cdot n_2! \cdot ... \cdot n_k!}$$

Step 1 - Choose first group:
Choose 5 people from 10: C(10, 5) = 252

Step 2 - Choose second group:
From remaining 5 people, choose 4: C(5, 4) = 5

Continue for all groups:
C(10,5) = 252
C(5,4) = 5
C(1,1) = 1 (last group)

Step 3 - Multiply:
Total ways = 252 × 5 × 1 (last group)
= 1260

Simplified formula:
= 10! / (5! × 4! × 1!)
= 3628800 / (120 × 24 × 1)
= 1260

Key Insight: Since groups have different sizes, we don't divide by k! (they're naturally distinguishable by their sizes).

Contrast with equal groups:
- If groups were same size: would divide by k!
- Here, sizes differ: no division needed

Verification: Sum of group sizes = 10 = 10 ✓

Question 3

In how many ways can 11 distinct people be divided into 4 groups of sizes 5, 3, 2, 1 (groups are unlabeled but have different sizes)?
Step-by-Step Solution:

Concept: Partitioning into groups of specified sizes. When group sizes are different, groups are automatically distinguishable by size.

Given:
- Total people: 11
- Group sizes: 5, 3, 2, 1
- Groups are unlabeled (no names like Team A, Team B)

Formula:
$$\frac{n!}{n_1! \cdot n_2! \cdot ... \cdot n_k!}$$

Step 1 - Choose first group:
Choose 5 people from 11: C(11, 5) = 462

Step 2 - Choose second group:
From remaining 6 people, choose 3: C(6, 3) = 20

Continue for all groups:
C(11,5) = 462
C(6,3) = 20
C(3,2) = 3
C(1,1) = 1 (last group)

Step 3 - Multiply:
Total ways = 462 × 20 × 3 × 1 (last group)
= 27720

Simplified formula:
= 11! / (5! × 3! × 2! × 1!)
= 39916800 / (120 × 6 × 2 × 1)
= 27720

Key Insight: Since groups have different sizes, we don't divide by k! (they're naturally distinguishable by their sizes).

Contrast with equal groups:
- If groups were same size: would divide by k!
- Here, sizes differ: no division needed

Verification: Sum of group sizes = 11 = 11 ✓

Question 4

In how many ways can 9 distinct people be divided into 4 groups of sizes 5, 3, 1 (groups are unlabeled but have different sizes)?
Step-by-Step Solution:

Concept: Partitioning into groups of specified sizes. When group sizes are different, groups are automatically distinguishable by size.

Given:
- Total people: 9
- Group sizes: 5, 3, 1
- Groups are unlabeled (no names like Team A, Team B)

Formula:
$$\frac{n!}{n_1! \cdot n_2! \cdot ... \cdot n_k!}$$

Step 1 - Choose first group:
Choose 5 people from 9: C(9, 5) = 126

Step 2 - Choose second group:
From remaining 4 people, choose 3: C(4, 3) = 4

Continue for all groups:
C(9,5) = 126
C(4,3) = 4
C(1,1) = 1 (last group)

Step 3 - Multiply:
Total ways = 126 × 4 × 1 (last group)
= 504

Simplified formula:
= 9! / (5! × 3! × 1!)
= 362880 / (120 × 6 × 1)
= 504

Key Insight: Since groups have different sizes, we don't divide by k! (they're naturally distinguishable by their sizes).

Contrast with equal groups:
- If groups were same size: would divide by k!
- Here, sizes differ: no division needed

Verification: Sum of group sizes = 9 = 9 ✓

Question 5

In how many ways can 11 distinct people be divided into 4 groups of sizes 5, 3, 2, 1 (groups are unlabeled but have different sizes)?
Step-by-Step Solution:

Concept: Partitioning into groups of specified sizes. When group sizes are different, groups are automatically distinguishable by size.

Given:
- Total people: 11
- Group sizes: 5, 3, 2, 1
- Groups are unlabeled (no names like Team A, Team B)

Formula:
$$\frac{n!}{n_1! \cdot n_2! \cdot ... \cdot n_k!}$$

Step 1 - Choose first group:
Choose 5 people from 11: C(11, 5) = 462

Step 2 - Choose second group:
From remaining 6 people, choose 3: C(6, 3) = 20

Continue for all groups:
C(11,5) = 462
C(6,3) = 20
C(3,2) = 3
C(1,1) = 1 (last group)

Step 3 - Multiply:
Total ways = 462 × 20 × 3 × 1 (last group)
= 27720

Simplified formula:
= 11! / (5! × 3! × 2! × 1!)
= 39916800 / (120 × 6 × 2 × 1)
= 27720

Key Insight: Since groups have different sizes, we don't divide by k! (they're naturally distinguishable by their sizes).

Contrast with equal groups:
- If groups were same size: would divide by k!
- Here, sizes differ: no division needed

Verification: Sum of group sizes = 11 = 11 ✓

Question 6

In how many ways can 10 distinct people be divided into 4 groups of sizes 5, 4, 1 (groups are unlabeled but have different sizes)?
Step-by-Step Solution:

Concept: Partitioning into groups of specified sizes. When group sizes are different, groups are automatically distinguishable by size.

Given:
- Total people: 10
- Group sizes: 5, 4, 1
- Groups are unlabeled (no names like Team A, Team B)

Formula:
$$\frac{n!}{n_1! \cdot n_2! \cdot ... \cdot n_k!}$$

Step 1 - Choose first group:
Choose 5 people from 10: C(10, 5) = 252

Step 2 - Choose second group:
From remaining 5 people, choose 4: C(5, 4) = 5

Continue for all groups:
C(10,5) = 252
C(5,4) = 5
C(1,1) = 1 (last group)

Step 3 - Multiply:
Total ways = 252 × 5 × 1 (last group)
= 1260

Simplified formula:
= 10! / (5! × 4! × 1!)
= 3628800 / (120 × 24 × 1)
= 1260

Key Insight: Since groups have different sizes, we don't divide by k! (they're naturally distinguishable by their sizes).

Contrast with equal groups:
- If groups were same size: would divide by k!
- Here, sizes differ: no division needed

Verification: Sum of group sizes = 10 = 10 ✓

Question 7

In how many ways can 10 distinct people be divided into 4 groups of sizes 7, 2, 1 (groups are unlabeled but have different sizes)?
Step-by-Step Solution:

Concept: Partitioning into groups of specified sizes. When group sizes are different, groups are automatically distinguishable by size.

Given:
- Total people: 10
- Group sizes: 7, 2, 1
- Groups are unlabeled (no names like Team A, Team B)

Formula:
$$\frac{n!}{n_1! \cdot n_2! \cdot ... \cdot n_k!}$$

Step 1 - Choose first group:
Choose 7 people from 10: C(10, 7) = 120

Step 2 - Choose second group:
From remaining 3 people, choose 2: C(3, 2) = 3

Continue for all groups:
C(10,7) = 120
C(3,2) = 3
C(1,1) = 1 (last group)

Step 3 - Multiply:
Total ways = 120 × 3 × 1 (last group)
= 360

Simplified formula:
= 10! / (7! × 2! × 1!)
= 3628800 / (5040 × 2 × 1)
= 360

Key Insight: Since groups have different sizes, we don't divide by k! (they're naturally distinguishable by their sizes).

Contrast with equal groups:
- If groups were same size: would divide by k!
- Here, sizes differ: no division needed

Verification: Sum of group sizes = 10 = 10 ✓

Question 8

In how many ways can 12 distinct people be divided into 3 groups of sizes 7, 3, 2 (groups are unlabeled but have different sizes)?
Step-by-Step Solution:

Concept: Partitioning into groups of specified sizes. When group sizes are different, groups are automatically distinguishable by size.

Given:
- Total people: 12
- Group sizes: 7, 3, 2
- Groups are unlabeled (no names like Team A, Team B)

Formula:
$$\frac{n!}{n_1! \cdot n_2! \cdot ... \cdot n_k!}$$

Step 1 - Choose first group:
Choose 7 people from 12: C(12, 7) = 792

Step 2 - Choose second group:
From remaining 5 people, choose 3: C(5, 3) = 10

Continue for all groups:
C(12,7) = 792
C(5,3) = 10
C(2,2) = 1 (last group)

Step 3 - Multiply:
Total ways = 792 × 10 × 1 (last group)
= 7920

Simplified formula:
= 12! / (7! × 3! × 2!)
= 479001600 / (5040 × 6 × 2)
= 7920

Key Insight: Since groups have different sizes, we don't divide by k! (they're naturally distinguishable by their sizes).

Contrast with equal groups:
- If groups were same size: would divide by k!
- Here, sizes differ: no division needed

Verification: Sum of group sizes = 12 = 12 ✓

Question 9

In how many ways can 11 distinct people be divided into 4 groups of sizes 5, 3, 2, 1 (groups are unlabeled but have different sizes)?
Step-by-Step Solution:

Concept: Partitioning into groups of specified sizes. When group sizes are different, groups are automatically distinguishable by size.

Given:
- Total people: 11
- Group sizes: 5, 3, 2, 1
- Groups are unlabeled (no names like Team A, Team B)

Formula:
$$\frac{n!}{n_1! \cdot n_2! \cdot ... \cdot n_k!}$$

Step 1 - Choose first group:
Choose 5 people from 11: C(11, 5) = 462

Step 2 - Choose second group:
From remaining 6 people, choose 3: C(6, 3) = 20

Continue for all groups:
C(11,5) = 462
C(6,3) = 20
C(3,2) = 3
C(1,1) = 1 (last group)

Step 3 - Multiply:
Total ways = 462 × 20 × 3 × 1 (last group)
= 27720

Simplified formula:
= 11! / (5! × 3! × 2! × 1!)
= 39916800 / (120 × 6 × 2 × 1)
= 27720

Key Insight: Since groups have different sizes, we don't divide by k! (they're naturally distinguishable by their sizes).

Contrast with equal groups:
- If groups were same size: would divide by k!
- Here, sizes differ: no division needed

Verification: Sum of group sizes = 11 = 11 ✓

Question 10

In how many ways can 10 distinct people be divided into 3 groups of sizes 6, 3, 1 (groups are unlabeled but have different sizes)?
Step-by-Step Solution:

Concept: Partitioning into groups of specified sizes. When group sizes are different, groups are automatically distinguishable by size.

Given:
- Total people: 10
- Group sizes: 6, 3, 1
- Groups are unlabeled (no names like Team A, Team B)

Formula:
$$\frac{n!}{n_1! \cdot n_2! \cdot ... \cdot n_k!}$$

Step 1 - Choose first group:
Choose 6 people from 10: C(10, 6) = 210

Step 2 - Choose second group:
From remaining 4 people, choose 3: C(4, 3) = 4

Continue for all groups:
C(10,6) = 210
C(4,3) = 4
C(1,1) = 1 (last group)

Step 3 - Multiply:
Total ways = 210 × 4 × 1 (last group)
= 840

Simplified formula:
= 10! / (6! × 3! × 1!)
= 3628800 / (720 × 6 × 1)
= 840

Key Insight: Since groups have different sizes, we don't divide by k! (they're naturally distinguishable by their sizes).

Contrast with equal groups:
- If groups were same size: would divide by k!
- Here, sizes differ: no division needed

Verification: Sum of group sizes = 10 = 10 ✓

Question 11

In how many ways can 11 distinct people be divided into 3 groups of sizes 8, 2, 1 (groups are unlabeled but have different sizes)?
Step-by-Step Solution:

Concept: Partitioning into groups of specified sizes. When group sizes are different, groups are automatically distinguishable by size.

Given:
- Total people: 11
- Group sizes: 8, 2, 1
- Groups are unlabeled (no names like Team A, Team B)

Formula:
$$\frac{n!}{n_1! \cdot n_2! \cdot ... \cdot n_k!}$$

Step 1 - Choose first group:
Choose 8 people from 11: C(11, 8) = 165

Step 2 - Choose second group:
From remaining 3 people, choose 2: C(3, 2) = 3

Continue for all groups:
C(11,8) = 165
C(3,2) = 3
C(1,1) = 1 (last group)

Step 3 - Multiply:
Total ways = 165 × 3 × 1 (last group)
= 495

Simplified formula:
= 11! / (8! × 2! × 1!)
= 39916800 / (40320 × 2 × 1)
= 495

Key Insight: Since groups have different sizes, we don't divide by k! (they're naturally distinguishable by their sizes).

Contrast with equal groups:
- If groups were same size: would divide by k!
- Here, sizes differ: no division needed

Verification: Sum of group sizes = 11 = 11 ✓

Question 12

In how many ways can 11 distinct people be divided into 4 groups of sizes 8, 2, 1 (groups are unlabeled but have different sizes)?
Step-by-Step Solution:

Concept: Partitioning into groups of specified sizes. When group sizes are different, groups are automatically distinguishable by size.

Given:
- Total people: 11
- Group sizes: 8, 2, 1
- Groups are unlabeled (no names like Team A, Team B)

Formula:
$$\frac{n!}{n_1! \cdot n_2! \cdot ... \cdot n_k!}$$

Step 1 - Choose first group:
Choose 8 people from 11: C(11, 8) = 165

Step 2 - Choose second group:
From remaining 3 people, choose 2: C(3, 2) = 3

Continue for all groups:
C(11,8) = 165
C(3,2) = 3
C(1,1) = 1 (last group)

Step 3 - Multiply:
Total ways = 165 × 3 × 1 (last group)
= 495

Simplified formula:
= 11! / (8! × 2! × 1!)
= 39916800 / (40320 × 2 × 1)
= 495

Key Insight: Since groups have different sizes, we don't divide by k! (they're naturally distinguishable by their sizes).

Contrast with equal groups:
- If groups were same size: would divide by k!
- Here, sizes differ: no division needed

Verification: Sum of group sizes = 11 = 11 ✓

Question 13

In how many ways can 8 distinct people be divided into 4 groups of sizes 4, 3, 1 (groups are unlabeled but have different sizes)?
Step-by-Step Solution:

Concept: Partitioning into groups of specified sizes. When group sizes are different, groups are automatically distinguishable by size.

Given:
- Total people: 8
- Group sizes: 4, 3, 1
- Groups are unlabeled (no names like Team A, Team B)

Formula:
$$\frac{n!}{n_1! \cdot n_2! \cdot ... \cdot n_k!}$$

Step 1 - Choose first group:
Choose 4 people from 8: C(8, 4) = 70

Step 2 - Choose second group:
From remaining 4 people, choose 3: C(4, 3) = 4

Continue for all groups:
C(8,4) = 70
C(4,3) = 4
C(1,1) = 1 (last group)

Step 3 - Multiply:
Total ways = 70 × 4 × 1 (last group)
= 280

Simplified formula:
= 8! / (4! × 3! × 1!)
= 40320 / (24 × 6 × 1)
= 280

Key Insight: Since groups have different sizes, we don't divide by k! (they're naturally distinguishable by their sizes).

Contrast with equal groups:
- If groups were same size: would divide by k!
- Here, sizes differ: no division needed

Verification: Sum of group sizes = 8 = 8 ✓

Question 14

In how many ways can 11 distinct people be divided into 4 groups of sizes 6, 4, 1 (groups are unlabeled but have different sizes)?
Step-by-Step Solution:

Concept: Partitioning into groups of specified sizes. When group sizes are different, groups are automatically distinguishable by size.

Given:
- Total people: 11
- Group sizes: 6, 4, 1
- Groups are unlabeled (no names like Team A, Team B)

Formula:
$$\frac{n!}{n_1! \cdot n_2! \cdot ... \cdot n_k!}$$

Step 1 - Choose first group:
Choose 6 people from 11: C(11, 6) = 462

Step 2 - Choose second group:
From remaining 5 people, choose 4: C(5, 4) = 5

Continue for all groups:
C(11,6) = 462
C(5,4) = 5
C(1,1) = 1 (last group)

Step 3 - Multiply:
Total ways = 462 × 5 × 1 (last group)
= 2310

Simplified formula:
= 11! / (6! × 4! × 1!)
= 39916800 / (720 × 24 × 1)
= 2310

Key Insight: Since groups have different sizes, we don't divide by k! (they're naturally distinguishable by their sizes).

Contrast with equal groups:
- If groups were same size: would divide by k!
- Here, sizes differ: no division needed

Verification: Sum of group sizes = 11 = 11 ✓

Question 15

In how many ways can 11 distinct people be divided into 4 groups of sizes 8, 2, 1 (groups are unlabeled but have different sizes)?
Step-by-Step Solution:

Concept: Partitioning into groups of specified sizes. When group sizes are different, groups are automatically distinguishable by size.

Given:
- Total people: 11
- Group sizes: 8, 2, 1
- Groups are unlabeled (no names like Team A, Team B)

Formula:
$$\frac{n!}{n_1! \cdot n_2! \cdot ... \cdot n_k!}$$

Step 1 - Choose first group:
Choose 8 people from 11: C(11, 8) = 165

Step 2 - Choose second group:
From remaining 3 people, choose 2: C(3, 2) = 3

Continue for all groups:
C(11,8) = 165
C(3,2) = 3
C(1,1) = 1 (last group)

Step 3 - Multiply:
Total ways = 165 × 3 × 1 (last group)
= 495

Simplified formula:
= 11! / (8! × 2! × 1!)
= 39916800 / (40320 × 2 × 1)
= 495

Key Insight: Since groups have different sizes, we don't divide by k! (they're naturally distinguishable by their sizes).

Contrast with equal groups:
- If groups were same size: would divide by k!
- Here, sizes differ: no division needed

Verification: Sum of group sizes = 11 = 11 ✓

Question 16

In how many ways can 10 distinct people be divided into 3 groups of sizes 9, 1 (groups are unlabeled but have different sizes)?
Step-by-Step Solution:

Concept: Partitioning into groups of specified sizes. When group sizes are different, groups are automatically distinguishable by size.

Given:
- Total people: 10
- Group sizes: 9, 1
- Groups are unlabeled (no names like Team A, Team B)

Formula:
$$\frac{n!}{n_1! \cdot n_2! \cdot ... \cdot n_k!}$$

Step 1 - Choose first group:
Choose 9 people from 10: C(10, 9) = 10

Step 2 - Choose second group:
From remaining 1 people, choose 1: C(1, 1) = 1

Continue for all groups:
C(10,9) = 10
C(1,1) = 1 (last group)

Step 3 - Multiply:
Total ways = 10 × 1 (last group)
= 10

Simplified formula:
= 10! / (9! × 1!)
= 3628800 / (362880 × 1)
= 10

Key Insight: Since groups have different sizes, we don't divide by k! (they're naturally distinguishable by their sizes).

Contrast with equal groups:
- If groups were same size: would divide by k!
- Here, sizes differ: no division needed

Verification: Sum of group sizes = 10 = 10 ✓

Question 17

In how many ways can 10 distinct people be divided into 4 groups of sizes 7, 2, 1 (groups are unlabeled but have different sizes)?
Step-by-Step Solution:

Concept: Partitioning into groups of specified sizes. When group sizes are different, groups are automatically distinguishable by size.

Given:
- Total people: 10
- Group sizes: 7, 2, 1
- Groups are unlabeled (no names like Team A, Team B)

Formula:
$$\frac{n!}{n_1! \cdot n_2! \cdot ... \cdot n_k!}$$

Step 1 - Choose first group:
Choose 7 people from 10: C(10, 7) = 120

Step 2 - Choose second group:
From remaining 3 people, choose 2: C(3, 2) = 3

Continue for all groups:
C(10,7) = 120
C(3,2) = 3
C(1,1) = 1 (last group)

Step 3 - Multiply:
Total ways = 120 × 3 × 1 (last group)
= 360

Simplified formula:
= 10! / (7! × 2! × 1!)
= 3628800 / (5040 × 2 × 1)
= 360

Key Insight: Since groups have different sizes, we don't divide by k! (they're naturally distinguishable by their sizes).

Contrast with equal groups:
- If groups were same size: would divide by k!
- Here, sizes differ: no division needed

Verification: Sum of group sizes = 10 = 10 ✓

Question 18

In how many ways can 10 distinct people be divided into 3 groups of sizes 5, 3, 2 (groups are unlabeled but have different sizes)?
Step-by-Step Solution:

Concept: Partitioning into groups of specified sizes. When group sizes are different, groups are automatically distinguishable by size.

Given:
- Total people: 10
- Group sizes: 5, 3, 2
- Groups are unlabeled (no names like Team A, Team B)

Formula:
$$\frac{n!}{n_1! \cdot n_2! \cdot ... \cdot n_k!}$$

Step 1 - Choose first group:
Choose 5 people from 10: C(10, 5) = 252

Step 2 - Choose second group:
From remaining 5 people, choose 3: C(5, 3) = 10

Continue for all groups:
C(10,5) = 252
C(5,3) = 10
C(2,2) = 1 (last group)

Step 3 - Multiply:
Total ways = 252 × 10 × 1 (last group)
= 2520

Simplified formula:
= 10! / (5! × 3! × 2!)
= 3628800 / (120 × 6 × 2)
= 2520

Key Insight: Since groups have different sizes, we don't divide by k! (they're naturally distinguishable by their sizes).

Contrast with equal groups:
- If groups were same size: would divide by k!
- Here, sizes differ: no division needed

Verification: Sum of group sizes = 10 = 10 ✓

Question 19

In how many ways can 12 distinct people be divided into 3 groups of sizes 7, 3, 2 (groups are unlabeled but have different sizes)?
Step-by-Step Solution:

Concept: Partitioning into groups of specified sizes. When group sizes are different, groups are automatically distinguishable by size.

Given:
- Total people: 12
- Group sizes: 7, 3, 2
- Groups are unlabeled (no names like Team A, Team B)

Formula:
$$\frac{n!}{n_1! \cdot n_2! \cdot ... \cdot n_k!}$$

Step 1 - Choose first group:
Choose 7 people from 12: C(12, 7) = 792

Step 2 - Choose second group:
From remaining 5 people, choose 3: C(5, 3) = 10

Continue for all groups:
C(12,7) = 792
C(5,3) = 10
C(2,2) = 1 (last group)

Step 3 - Multiply:
Total ways = 792 × 10 × 1 (last group)
= 7920

Simplified formula:
= 12! / (7! × 3! × 2!)
= 479001600 / (5040 × 6 × 2)
= 7920

Key Insight: Since groups have different sizes, we don't divide by k! (they're naturally distinguishable by their sizes).

Contrast with equal groups:
- If groups were same size: would divide by k!
- Here, sizes differ: no division needed

Verification: Sum of group sizes = 12 = 12 ✓

Question 20

In how many ways can 10 distinct people be divided into 3 groups of sizes 6, 3, 1 (groups are unlabeled but have different sizes)?
Step-by-Step Solution:

Concept: Partitioning into groups of specified sizes. When group sizes are different, groups are automatically distinguishable by size.

Given:
- Total people: 10
- Group sizes: 6, 3, 1
- Groups are unlabeled (no names like Team A, Team B)

Formula:
$$\frac{n!}{n_1! \cdot n_2! \cdot ... \cdot n_k!}$$

Step 1 - Choose first group:
Choose 6 people from 10: C(10, 6) = 210

Step 2 - Choose second group:
From remaining 4 people, choose 3: C(4, 3) = 4

Continue for all groups:
C(10,6) = 210
C(4,3) = 4
C(1,1) = 1 (last group)

Step 3 - Multiply:
Total ways = 210 × 4 × 1 (last group)
= 840

Simplified formula:
= 10! / (6! × 3! × 1!)
= 3628800 / (720 × 6 × 1)
= 840

Key Insight: Since groups have different sizes, we don't divide by k! (they're naturally distinguishable by their sizes).

Contrast with equal groups:
- If groups were same size: would divide by k!
- Here, sizes differ: no division needed

Verification: Sum of group sizes = 10 = 10 ✓
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