The sides of a rectangular field are in the ratio 3 : 4. If the area of the field is 8112 sq. m, the cost of fencing the field @ 25 paise per metre is  Options:
A) Rs. 55.50 B) Rs. 67.50 C) Rs. 86.50 D) Rs. 91.00 E) None of these
Solution   Let length = (3x) metres and breadth = (4x) metres.   Then, 3x × 4x = 7600 ⇔ 12x2 = 8112 ⇔ x2 = 676 ⇔ x = 26   So, length = 78 m and breadth = 104 m.   Perimeter = [2(78 + 104)] m = 364 m.   ∴ Cost of fencing = Rs. (0.25 × 364) = Rs. 91. Answer Rs. 91.00
<result>D</result>
The sides of a rectangular field are in the ratio 3 : 4. If the area of the field is 8112 sq. m, the cost of fencing the field @ 25 paise per metre is