Correct Answer - Option 4 : 68 years
Given:
Average age of A, B, and C, 4 years ago = 34 years
Present average age of A and B = 28 years
Average age of C and D after 2 years = 65 years
Formula used:
Average = Sum of units/Number of units
Calculation:
Sum of age of A, B, and C, 4 years ago = 34 × 3 = 102 years
Present sum of their ages = 102 + (3 × 4) years
⇒ 102 + 12 years
⇒ 114 years
Now, Sum of age of A and B = 28 × 2 years
⇒ 56 years
Age of C = (114 – 56) years
⇒ 58 years
Age of C after 2 years = 60 years
Sum of age of C and D after 2 years = (65 × 2) years
⇒ 130 years
Age of D after 2 years = (130 – 60) years
⇒ 70 years
Present age of D = (70 – 2) years
⇒ 68 years
∴ The average age of D is 68 years