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Find Number of Family Members

Find Number of Family Members problems give the total sum or average age of a family and ask for the number of members. These problems test the fundamental relationship between sum, average, and count.

10Worksheets
200+Practice Questions
BeginnerDifficulty
1 hourHours to Master

What You'll Learn

Introduction & Overview Why This Matters How to Solve Pro Tips & Tricks
Shortcut Methods Common Mistakes Practice Worksheets Exam Importance

Introduction to Find Number of Family Members

Find Number of Family Members problems give the total sum or average age of a family and ask for the number of members. These problems test the fundamental relationship between sum, average, and count.

Prerequisites

Average formula Sum = Average × Count Basic division
Why This Matters: These problems appear in 1-2 questions in banking prelims. They test basic average concepts in a family context.

How to Solve Find Number of Family Members Problems

1

Step 1: Identify the given total sum of ages or the average

2

Step 2: Use the formula: Sum = Average × Number

3

Step 3: If sum is given, Number = Sum ÷ Average

4

Step 4: If only average is given, look for additional information

5

Step 5: Check if the number must be an integer

6

Step 6: Verify that the calculated number makes sense (positive integer)

7

Step 7: Answer the number of family members

Pro Strategy: Always remember the triangle relationship: Sum = Average × Count. If any two are known, the third can be found.

Example Problem

Example: The sum of ages of all members in a family is 120 years. If the average age is 30 years, how many members are there? Solution: Step 1: Sum = 120, Average = 30 Step 2: Number = Sum ÷ Average = 120 ÷ 30 = 4 Answer: 4 family members

Pro Tips & Tricks

  • Number of members = Total sum ÷ Average age
  • Total sum = Average × Number of members
  • Average = Total sum ÷ Number of members
  • The number of members must be a positive integer
  • If sum and average don't divide evenly, data may be inconsistent
  • Check if ages are reasonable for the family size

Shortcut Methods to Solve Faster

n = S/A where S = sum, A = average
A = S/n
S = A × n

Common Mistakes to Avoid

Multiplying instead of dividing
Forgetting that number must be integer
Using wrong formula (average instead of sum)
Not checking if family size is reasonable

Exam Importance

Find Number of Family Members is an important topic for various competitive exams. Here's how frequently it appears:

SSC CGL
1-2 questions
BANKING PO
1-2 questions
RAILWAYS RRB
1-2 questions
CAT
0-1 questions
INSURANCE
1-2 questions

Ready to Master Find Number of Family Members?

Start with Worksheet 1 and work your way up to expert level! Each worksheet includes:

20 practice questions
Detailed solutions
Step-by-step explanations
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