ABC26GN4401 · Area
Subject: General Aptitude · Chapter: Area · Exam: · Marks: · Difficulty:
A man walking at the speed of 4 kmph crosses a square field diagonally in 3 minutes. The area of the field is
(a)$18000 \mathrm{m}^{2}$
(b)$19000 \mathrm{m}^{2}$
(c)$20000 \mathrm{m}^{2}$
(d)$25000 \mathrm{m}^{2}$
Answer
Explanation
Speed of the man $=\left(4 \times \frac{5}{18}\right) \mathrm{m} / \mathrm{s}=\frac{10}{9} \mathrm{m} / \mathrm{s}$. Time taken $=(3 \times 60) \mathrm{sec}=180 \mathrm{sec}$. Length of diagonal $=($ speed × time $)=\left(\frac{10}{9} \times 180\right) \mathrm{m}=200 \mathrm{m}$. $$\begin{aligned} \text { Area of the field } & =\frac{1}{2} \times(\text { diagonal })^{2} \\ & =\left(\frac{1}{2} \times 200 \times 200\right) \mathrm{m}^{2}=20000 \mathrm{m}^{2} \end{aligned}$$
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