Paper 1 · Mathematical Reasoning and Aptitude
UGC NET December 2022 (21.02.2023) Shift-I
The average age of a family of 5 members three years ago was 17 years. In spite of the birth of a child in the family during these 3 years, the present average age of the family remains the same. What is the present age of the child?
A2 years ✓ Correct
B3 years
C2.5 years
D3.5 years
Correct answer: (A) 2 years — The child's present age is 2 years, so the answer is 2 years.
Explanation
★The child's present age is 2 years, so the answer is 2 years.
★Three years ago the 5 members had a total age of 5 times 17, which is 85.
★Over 3 years each of these 5 members ages by 3, adding 15 to the total.
★So without the child the present total for the 5 members is 100 years.
★Now the family has 6 members with the same average of 17, giving a total of 102.
★The child's age is this new total minus the total for the 5 members, which is 102 minus 100.
★That equals 2 years.
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