ABC26GN4534 · Area
Subject: General Aptitude · Chapter: Area · Exam: · Marks: · Difficulty:
A man runs round a circular field of radius 50 m at the speed of 12 km/hr. What is the time taken by the man to take twenty rounds of the field?
(a)30 min.
(b)32 min.
(c)34 min.
(d)None of these
Answer
Explanation
Speed $=12 \mathrm{km} / \mathrm{hr}=\left(12 \times \frac{5}{18}\right) \mathrm{m} / \mathrm{s}=\frac{10}{3} \mathrm{m} / \mathrm{s}$. Distance covered $=\left(20 \times 2 \times \frac{22}{7} \times 50\right) \mathrm{m}=\frac{44000}{7} \mathrm{m}$. Time taken = $$\begin{aligned} \frac{\text { Distance }}{\text { Speed }}=\left(\frac{4400}{7} \times \frac{3}{10}\right) s=\left(\frac{4400 \times 3}{7} \times \frac{1}{60}\right) \mathrm{min} & =\frac{220}{7} \mathrm{min} \\ & =31 \frac{3}{7} \mathrm{min} . \end{aligned}$$
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