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Question

The average age of a couple was 24 years. After their 1st and 2nd children (twins) were born, the average age of the family became 13.5 years. The average age of the family just after 3rd child was born was 13.2 years. The average age of the family after 4th child was born was 16 years. The current average age of the family is 19 years. What is the current age of the twin children?

CAT 2021

A
14 years
CORRECT ANSWER WRONG ANSWER
B
15 years
CORRECT ANSWER WRONG ANSWER
C
11 years
CORRECT ANSWER WRONG ANSWER
D
12 years
CORRECT ANSWER WRONG ANSWER
Solution

Correct option is

(D)

Explanatory Answer

Sum of the age of the couple = 24 * 2 = 48

after 1st and 2nd children , sum will be = 13.5* 4 = 54

difference will be = 6 yrs, OR After 6/2 = 3 years , the twin were born to the couple

after 3rd children , sum will be = 13.2 * 5 = 66 yrs ,

And difference = 66 - 54 = 12 yrs OR after 12/4 = 3 yrs , 3rd child was born ( couple + 2 children were already present . so 4)

so , after 4th children , sum = 16 * 6 = 96 yrs

difference = 96 -66 =30 OR after 30/5 = 6 yrs , 4th child was born

current sum = 19 * 6 = 114 yrs

difference 114 -96 = 18 yrs OR after 18 /6 = 3 yrs

the gap between the children are : 3 , 6 ,3 yrs

age of eldest ones = 3 + 6 + 3 = 12

hence , D is the correct option