The age of A 3 years hence is three times the age of B 5 years ago and A is 9 years younger than C. If the sum of the present age of A, B and C together is 78 years, then find the present age of C?
A. 39 years
B. 51 years
C. 42 years
D. 36 years
E. None of these
Sol:
Let the present age of B = x
And the present age of A = (x – 5) * 3 – 3 = 3x –
15 – 3 = 3x – 18
The present age C = 3x – 18 + 9 = 3x – 9
x + 3x – 18 + 3x – 9 = 78
7x = 105
x = 15
The present age of C = 3 * 15 – 9 = 36 years