Future Age Ratio

Future Age Ratio problems give the ratio of ages at a future date and require finding present ages. These problems test your ability to project ages forward and work with ratio equations.

10Worksheets
200+Practice Questions
IntermediateDifficulty
2-3 hoursHours to Master

Introduction to Future Age Ratio

Future Age Ratio problems give the ratio of ages at a future date and require finding present ages. These problems test your ability to project ages forward and work with ratio equations.

Prerequisites

Ratio concepts Future age calculation Cross multiplication Linear equations
Why This Matters: Future Age Ratio problems appear in 2-3 questions in SSC CGL and banking exams. They test understanding of how ratios change over time.

How to Solve Future Age Ratio Problems

1

Step 1: Let present ages be expressed using a ratio (e.g., A = ak, B = bk)

2

Step 2: Add the future years to each age: (A+n) and (B+n)

3

Step 3: Set up the future ratio equation: (A+n)/(B+n) = c/d

4

Step 4: Cross-multiply: d(A+n) = c(B+n)

5

Step 5: Substitute A = ak, B = bk

6

Step 6: Solve for k

7

Step 7: Calculate present ages and verify the future ratio

Pro Strategy: Use the k-method for present ratio. The future ratio gives an equation to solve for k. The ratio always moves toward 1:1 as time increases.

Example Problem

Example: Present ages of A and B are in ratio 4:5. After 6 years, the ratio becomes 5:6. Find their present ages. Solution: Step 1: Let A = 4k, B = 5k Step 2: After 6 years: (4k+6)/(5k+6) = 5/6 Step 3: Cross multiply: 6(4k+6) = 5(5k+6) Step 4: 24k + 36 = 25k + 30 Step 5: 36 - 30 = 25k - 24k → 6 = k Step 6: A = 4×6 = 24, B = 5×6 = 30 years Answer: A = 24, B = 30 years

Pro Tips & Tricks

  • Present ratio a:b → ages ak and bk
  • Future ratio after n years: (ak+n)/(bk+n) = c/d
  • Cross multiplication avoids fractions
  • k = n(d-c)/(bc-ad) formula for quick solving
  • The older person's ratio term is usually larger initially
  • The ratio approaches 1:1 as n increases

Shortcut Methods to Solve Faster

Formula: k = n(d-c)/(bc-ad)
For a:b to c:d after n years, k = n(c-d)/(ad-bc)
The difference in ratio terms decreases over time

Common Mistakes to Avoid

Using present ratio instead of future ratio in equation
Forgetting to add n to both ages
Cross multiplication errors
Swapping numerator and denominator incorrectly

Exam Importance

Future Age Ratio is an important topic for various competitive exams. Here's how frequently it appears:

SSC CGL
2-3 questions
BANKING PO
2-3 questions
RAILWAYS RRB
2-3 questions
CAT
1-2 questions
INSURANCE
2-3 questions

Ready to Master Future Age Ratio?

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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