Question

if A, B, C average age is 21, and if A, B, C, D average age is 23, then what will be the age of D?
​

Answer 1

A+B+C/3=21

A+B+C=63 (1)

A+B+C+D/4=23

A+B+C+D=92 (2)

SUBTRACT 1 FROM 2

A+B+C+D-A-B-C=92-63

D=29

D's age is 29 yrs.

Answer 2

Answer:

hope this helps. Thank you