Five children, three years apart — Aptitude Question
Five children, three years apart: The sum of the ages of five children born at intervals of 3 years each is 50 years. Answer and worked solution on CodeKairo.
- Topic: Problems on Ages
- Section: Quantitative Aptitude
- Difficulty: Medium
- Time target: 75 seconds
Question
The sum of the ages of five children born at intervals of 3 years each is 50 years. What is the age of the youngest?
Options
- 4
- 6
- 8
- 10
Show the answer and the worked solution
Correct answer: A. 4
Worked solution
- Ages: x, x + 3, x + 6, x + 9, x + 12.
- Sum = 5x + 30 = 50 → x = 4.
- Check: 4 + 7 + 10 + 13 + 16 = 50. ✓
Answer: 4.
The idea
For evenly spaced ages the sum is count × middle age, so the middle child is 10 and the youngest is 6 less. Both routes give 4.
Shortcut. Take the gaps off first: the four elder children carry 3 + 6 + 9 + 12 = 30 extra years, so the remaining 20 is shared equally five ways — the youngest is 4.
Common trap. 10 is the middle child's age (50 ÷ 5); dividing the total by five gives the average, which belongs to the third child, not the youngest.