Subject: General Aptitude · Chapter: Time and Distance · Exam: 2006 · Marks: · Difficulty:
$A$ runs twice as fast as $B$ and $B$ runs thrice as fast as $C$. The distance covered by $C$ in 72 minutes, will be covered by $A$ in
(a)12 minutes
(b)16 minutes
(c)18 minutes
(d)24 minutes
Answer
Answer (as printed): A
Explanation
Let C's speed $=x \mathrm{km} / \mathrm{hr}$. Then, $B^{\prime} \mathrm{s}$ speed $=3 x \mathrm{km} / \mathrm{hr}$ and $A$ 's speed $=6 x \mathrm{km} / \mathrm{hr}$. ∴ Ratio of speeds of $A, B, C=6 x: 3 x: x=6: 3: 1$. Ratio of times taken $=\frac{1}{6}: \frac{1}{3}: 1=1: 2: 6$. If $C$ takes 6 min, then $A$ takes 1 min. If $C$ takes 72 min, then $A$ takes $\left(\frac{1}{6} \times 72\right) \min =12 \min$.