Subject: General Aptitude · Chapter: Area · Exam: · Marks: · Difficulty:
The cost of fencing a square field @ ₹ 20 per metre is ₹ 10,080. How much will it cost to lay a three metre wide pavement along the fencing inside the field @ ₹ 50 per sq. metre?
(a)₹ 37,350
(b)₹ 73,800
(c)₹ 77,400
(d)None of these
Answer
Answer (as printed): B
Explanation
Perimeter $=\frac{\text { Total cost }}{\text { Cost per } \mathrm{m}}=\frac{10080}{20} \mathrm{m}=504 \mathrm{m}$. Side of the square $=\frac{504}{4} \mathrm{m}=126 \mathrm{m}$. Breadth of the pavement = 3 m. Side of inner square $=(126-6) \mathrm{m}=120 \mathrm{m}$. Area of the pavement $=[(126 \times 126)-(120 \times 120)] \mathrm{m}^{2}$ $$\begin{aligned} & =[(126+120)(126-120)] \mathrm{m}^{2} \\ & =(246 \times 6) \mathrm{m}^{2} \end{aligned}$$ ∴ Cost of pavement $=₹(246 \times 6 \times 50)=₹ 73800$.