A father is now three times as old as his son. Five years back, he was four times as old as his son. The age of the son (in years) is Pick
A) 12
B) 15
C) 18
D) 20
E) 25
If father's age is F and son's age is S, then   F=3S   and   F-5 = 4*(S-5)   3S-5 =4S-20   S=15   F=45 years   ANSWER:15
<result>B</result>
A father is now three times as old as his son. Five years back, he was four times as old as his son. The age of the son (in years) is