Problems on Ages

JKSSB Junior Engineer (Mechanical) · Mathematics · 81 practice questions with answers and explanations: 43 Easy, 37 Medium, 1 Hard.

Sample questions

Sample Easy question 1

The ages of Amit and Farah are in the ratio 3 : 5, and the difference between their ages is 16 years. What is Amit's age (in years)?

  1. 24
  2. 32
  3. 40
  4. 16
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Answer: A. One part = 16/2 = 8; Amit's age = 3 × 8 = 24 years.

Sample Easy question 2

The present ages of two brothers are 16 and 24 years. What will be the ratio of their ages after 2 years?

  1. 2 : 3
  2. 7 : 11
  3. 9 : 13
  4. 13 : 9
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Answer: C. After 2 years the ages are 18 and 26, a ratio of 9 : 13.

Sample Easy question 3

The average age of 5 friends is 25 years. A new friend aged 39 years joins the group. What is the new average age (in years, to one decimal place if needed)?

  1. 32.8
  2. 27.3
  3. 32
  4. 25
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Answer: B. New average = (5×25 + 39)/6 = 27.3 years.

Sample Medium question 4

The average age of three persons is 24 years. If two of them are 20 and 26 years old, find the age of the third.

  1. 28
  2. 22
  3. 26
  4. 30
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Answer: C. Total = 3 × 24 = 72. Third = 72 − (20 + 26) = 26.

Sample Medium question 5

The average age of 5 students is 12 years. When the teacher's age is included, the average becomes 14 years. Find the teacher's age.

  1. 28
  2. 24
  3. 26
  4. 30
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Answer: B. Total with teacher = 6 × 14 = 84; students' total = 5 × 12 = 60. Teacher = 84 − 60 = 24.

Sample Medium question 6

A is older than B by 6 years, and their present ages are in the ratio 7 : 4. Find B's present age.

  1. 14
  2. 10
  3. 8
  4. 6
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Answer: C. 7k − 4k = 3k = 6, so k = 2 and B = 4k = 8.

Sample Hard question 7

Ten years ago a father was 12 times as old as his son; ten years from now he will be twice as old as his son. Find the son's present age.

  1. 14
  2. 15
  3. 10
  4. 12
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Answer: D. f − 10 = 12(s − 10) and f + 10 = 2(s + 10). Eliminating f: 12s − 110 = 2s + 10, so s = 12 (and f = 34).

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