Subject: General Aptitude · Chapter: Area · Exam: · Marks: · Difficulty:
In order to reach his office on time, Mr. Roy goes through the middle passage of a round fort which he takes 14 minutes to pass through. However, on a certain day, due to repairs, the straight road being blocked, he had to take the roundabout way as a result of which he reached his office late. How late was he?
(a)6 min
(b)8 min
(c)12 min
(d)$7 \frac{1}{2} \mathrm{min}$
Answer
Answer (as printed): B
Explanation
Let the diameter of the round fort be $D$. Distance through the middle passage = D. Roundabout distance $=\frac{\pi D}{2}$. Time taken to cover distance $D=14 \mathrm{min}$. Time taken to cover distance $$\frac{\pi D}{2}=\frac{14}{D} \times \frac{\pi D}{2}=7 \pi=\left(7 \times \frac{22}{7}\right) \mathrm{min}=22 \mathrm{min} .$$ ∴ Required time difference $=(22-14) \mathrm{min}=8 \mathrm{min}$.