The sides of a rectangular field are in the ratio 3 : 4. If the area of the field is 7500 sq. m, the cost of fencing the field @ 25 paise per metre is
Pick.
A) Rs. 55.50	B) Rs. 67.50	C) Rs. 86.50	D) Rs. 87.50	E) None of these
Solution   Let length = (3x) metres and breadth = (4x) metres.   Then, 3x × 4x = 7500 ⇔ 12x2 = 7500 ⇔ x2 = 625 ⇔ x = 25.   So, length = 75 m and breadth = 100 m.   Perimeter = [2(75 + 100)] m = 350 m.   ∴ Cost of fencing = Rs. (0.25 × 350) = Rs. 87.50. Answer Rs. 87.50
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The sides of a rectangular field are in the ratio 3 : 4. If the area of the field is 7500 sq. m, the cost of fencing the field @ 25 paise per metre is