The sides of a rectangular field are in the ratio 3 : 4. If the area of the field is 10800 sq. m, the cost of fencing the field @ 25 paise per metre is	Answers
A) rs . 55.50	B) rs . 67.50	C) rs . 86.50	D) rs . 105.00	E) none of these

Rationale: "solution let length = ( 3 x ) metres and breadth = ( 4 x ) metres . then , 3 x × 4 x = 10800 ⇔ 12 x 2 = 10800 ⇔ x 2 = 900 ⇔ x = 30 . so , length = 90 m and breadth = 120 m . perimeter = [ 2 ( 90 + 120 ) ] m = 420 m . ∴ cost of fencing = rs . ( 0.25 × 420 ) = rs . 105.00 . answer d"
Answer: D