Read the information carefully and answer the question given below. Seven…

2025

Read the information carefully and answer the question given below.

Seven persons A, B, C, D, E, F and G were born in seven different years — 1947, 1959, 1964, 1973, 1978, 1988 and 2001 — on the same month and the same date. (Take 2025 as the base year for age calculation.)
• The sum of the ages of C and F is equal to the age of D.
• G's age is divisible by 6.
• The total of the ages of A and G is a prime number.
• A is just older than F.
• The sum of the ages of B and A is divisible by 5.

What is the difference between the ages of C and D?

Answer: D. 37 yearsConceptIn an age-and-year puzzle, a person's age in a fixed base year is found by subtracting the birth year from the base year. Once every age is known, the…

  1. A.

    12 years

  2. B.

    10 years

  3. C.

    24 years

  4. D.

    37 years

  5. E.

    38 years

Attempted by 31 students.

Show answer & explanation

Correct answer: D

Concept

In an age-and-year puzzle, a person's age in a fixed base year is found by subtracting the birth year from the base year. Once every age is known, the verbal clues become numeric equations and divisibility/prime conditions that you test against the fixed set of ages until exactly one assignment of people to ages survives.

Step 1 — Convert birth years to ages (base year 2025)

Age = 2025 − (birth year), giving the fixed age set:

  • 1947 → 78

  • 1959 → 66

  • 1964 → 61

  • 1973 → 52

  • 1978 → 47

  • 1988 → 37

  • 2001 → 24

Step 2 — Apply the clues in order

  1. G's age is divisible by 6. Among {78, 66, 61, 52, 47, 37, 24}, the multiples of 6 are 78, 66 and 24, so G is one of these.

  2. A + G is a prime number, and B + A is divisible by 5. Testing the allowed G values against the remaining ages, A = 47 with G = 66 gives A + G = 113 (prime) and B = 78 with B + A = 125 (divisible by 5).

  3. A is just older than F, i.e. A's age is the next age immediately above F's in the sorted list. With A = 47, the age just below it is 37, so F = 37.

  4. C + F = D. The ages still free are 24, 52 and 61. Choosing C = 24 gives C + F = 24 + 37 = 61, which is an available age, so D = 61 and E = 52.

Step 3 — Final assignment

  • A = 47, B = 78, C = 24, D = 61, E = 52, F = 37, G = 66.

Step 4 — Answer the question

Difference between the ages of C and D = |24 − 61| = 37 years.

Cross-check

C + F = 24 + 37 = 61 = D ✓; G = 66 is divisible by 6 ✓; A + G = 113 is prime ✓; B + A = 125 is divisible by 5 ✓; 47 is immediately above 37 in the sorted ages, so A is just older than F ✓. All clues hold, so the assignment is unique.

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