Subject: General Aptitude · Chapter: Problems on Ages · Exam: 2009 · Marks: · Difficulty:
The present ages of Amit and his father are in the ratio 2 : 5 respectively. Four years hence, the ratio of their ages becomes 5 : 11 respectively. What was the father's age five years ago? (Bank P.O., 2009)
(a)30 years
(b)35 years
(c)40 years
(d)45 years
(e)None of these
Answer
Answer (as printed): B
Explanation
Let Amit's age be $2x$ years. Then, his father's age $=5x$ years. $$\frac{2x+4}{5x+4}=\frac{5}{11} \Rightarrow 11(2x+4)=5(5x+4) \Rightarrow 22x+44=25x+20 \Rightarrow 3x=24 \Rightarrow x=8.$$ Father's age 5 years ago $=(5x-5)$ years $=(5\times 8-5)$ years $=35$ years.
Explanation as extracted from the printed page; notation may be imperfect.