1.  The present age of Ravi's father is four times Ravi's present age. Five years back, Ravi's father was seven times as old as Ravi was at that time. What is the present age of Ravi's father ?
A. 84 yr
B. 70 yr
C. 40 yr
D. 35 yr

Answer: Option C

Explanation:

Let present age of Ravi be x.
Then, present age of Ravi's father = 4x
Now, 5 yr ago,
Ravi's father age = 7 x Ravi's age
4x - 5 = 7(x - 5)
4x - 5 = 7x - 35
3x = 30
 x = 10
Ravi's present age = x = 10 yr
Ravi's father's present age 4x = 4 x 10 = 40 yr