Question

6) Four years ago, the average age of A and B was 20 years. If today average age of A, B and C is 25 years, what will be age of C after 7 years?

Answer 1

Answer:

34 years

Step-by-step explanation:

Four years ago, avg. age of A and B is 20 years.

(A+B)/2 = 20

A+B = 40 years   ∵ [sum of ages of A and B, 4 years ago]

So, sum of the ages today,

= 40+4+4 = 48 years   ∵[A's and B's age added by 4]

Today, avg. age of A,B,C is 25 years.

(A+B+C)/3 = 25

(A+B+C) = 75 years    ∵[sum of ages of A, B and C today]

Substitute sum of the ages of A and B today

48+C = 75

C = 27 years   ∵[Current age of C]

C's age after 7 years

C = 27+7 = 34 years