Ratio Future

Ratio Future problems give the ratio of ages at some future date and ask for present ages or other relationships. These problems require projecting ages forward and setting up ratio equations.

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

Introduction to Ratio Future

Ratio Future problems give the ratio of ages at some future date and ask for present ages or other relationships. These problems require projecting ages forward and setting up ratio equations.

Prerequisites

Ratio concepts Future age calculation Linear equations
Why This Matters: Ratio Future problems appear in 2-3 questions in competitive exams. They test ability to work with future projections.

How to Solve Ratio Future Problems

1

Step 1: Let present ages be represented using a ratio (e.g., A:B = a:b → 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) = p/q

4

Step 4: Cross-multiply and solve for k

5

Step 5: Calculate present and future ages

6

Step 6: Verify the future ratio

Pro Strategy: Use the k-method for present ratio, then apply time shift to get future ages before setting up the future ratio equation.

Example Problem

Example: Present ages of A and B are in ratio 3:4. After 5 years, the ratio becomes 4:5. Find present ages. Solution: Step 1: Let A = 3k, B = 4k Step 2: After 5 years: (3k+5)/(4k+5) = 4/5 Step 3: Cross multiply: 5(3k+5) = 4(4k+5) → 15k + 25 = 16k + 20 Step 4: 25 - 20 = 16k - 15k → 5 = k Step 5: A = 15, B = 20 years Answer: A = 15, B = 20 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
  • The value of k is usually an integer or simple fraction
  • Check if ages increase logically
  • If future ratio is smaller than present ratio, the younger person catches up

Shortcut Methods to Solve Faster

k = n(c-d)/(ad - bc) formula for two persons
For a:b to c:d after n years: k = n(d-c)/(bc-ad)
Difference method: n = k(ad-bc)/(c-d)

Common Mistakes to Avoid

Using present ratio instead of future ratio in equation
Forgetting to add n to both ages
Cross multiplication errors
Not checking if k is positive and yields reasonable ages

Exam Importance

Ratio Future 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

Ready to Master Ratio Future?

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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