Average of the present age of A, B and C is equal to the age of C after 5 years. Present age of A is 2/3rd of the sum of the present age of B and C. B is 6 years elder than C. Find the present age of A.
a) 21 years
b) 18 years
c) 24 years
d) 15 years
e) None of these
Sol:
(A + B + C)/3 = C + 5
A + B + C = 3C + 15 —- (1)
(B + C) * 2/3 = A
A = (2B + 2C) * 1/3 —- (2)
From (1) and (2),
(2B + 2C) * 1/3 + B + C = 3C + 15
2B + 2C + 3B + 3C = 9C + 45
5B – 4C = 45 —- (3)
B – C = 6
B = C + 6 —- (4)
5 * (C + 6) – 4C = 45
5C + 30 – 4C = 45
C = 15 years
B = 15 + 6 = 21 years
A = (21 + 15) * 2/3 = 36 * 2/3 = 24 years
