Question

Five years ago, the average age of A,B,C and D was 45 years. By including X in the present lot their present average changes to 49 years. What is the present age of X?

Accepted Answer

B. Present average of A, B, C, D = $45 + 5 = 50$ years. Sum of present ages of A, B, C, D = $50 	imes 4 = 200$ years. Present average of A, B, C, D, X = 49 years. Sum of present ages of all five = $49 	imes 5 = 245$ years. Present age of X = $245 - 200 = 45$ years.

Average age calculation

Explanation

Practise this under exam conditions