Subject: General Aptitude · Chapter: Time and Distance · Exam: 2007 · Marks: · Difficulty:
The speeds of $A$ and $B$ are in the ratio 3 : 4. $A$ takes 20 minutes more than B to reach a destination. In what time does A reach the destination?
(a)$1 \frac{1}{3}$ hours
(b)$1 \frac{2}{3}$ hours
(c)2 hours
(d)$2 \frac{2}{3}$ hours
Answer
Answer (as printed): A
Explanation
Ratio of speeds $=3:4$. Ratio of times taken $=\frac{1}{3}:\frac{1}{4}=4:3$. Let $A$ and $B$ take $4x$ and $3x$ minutes respectively to reach a destination. Then, $4x-3x=20 \Leftrightarrow x=20$. $$\therefore \text{Time taken by A} = 4x = (4\times20)\text{ min} = 80\text{ min} = 1\frac{1}{3}\text{ hr}.$$
Explanation as extracted from the printed page; notation may be imperfect.