Younger by seven years — Problems on Ages Aptitude Question
Younger by seven years: Sachin is younger than Rahul by 7 years and their ages are in the ratio 7 : 9. Answer and worked solution on CodeKairo.
- Topic: Problems on Ages
- Section: Quantitative Aptitude
- Difficulty: Medium
- Time target: 60 seconds
Question
Sachin is younger than Rahul by 7 years and their ages are in the ratio 7 : 9. What is Sachin's age?
Options
- 22.5
- 24.5
- 26.5
- 28
Show the answer and the worked solution
Correct answer: B. 24.5
Worked solution
- Ages: 7x and 9x, so 9x − 7x = 2x = 7 → x = 3.5.
- Sachin = 7 × 3.5 = 24.5 years.
Answer: 24.5.
The idea
The difference of the ratio terms corresponds to the given difference in years. A non-integer x is perfectly acceptable here.
Shortcut. One part = 7 years ÷ (9 − 7) = 3.5, so Sachin = 7 × 3.5 = 24.5. His age must be a multiple of 3.5, which rules out 22.5 and 26.5 at once.
Common trap. 28 tempts as the only whole number and a multiple of 7, so it looks like '7 parts', but Rahul would then be 36 and the gap 8 years, not 7.