1.  The age of a man after 15 yr is 4 times the age of that man 15 yr before. His present age is :
A. 10 yr
B. 15 yr
C. 20 yr
D. 25 yr

Answer: Option D

Explanation:

Let present age of man be x yr.
According to the question,

x + 15 = 4(x - 15)

x + 15 = 4x - 60

3x = 75

x = 25