The ratio between the length and the breadth of a rectangular park is 3 : 2. If a man cycling along the boundary of the park at the speed of 12 km/hr completes one round in 8 minutes, the n the area of the park (in square metre) is :
Options:
A . 15360 square metre
B . 153600 square metre
C . 30720 square metre
D . 307200 square metre
Answer: Option B $${\text{Perimeter}} = $$ $${\text{Distance covered in 8 minutes}}$$$$\eqalign{ & \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = \left( {\frac{{12000}}{{60}} \times 8} \right)m \cr & \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = 1600{\text{ }}\,m \cr} $$ Let the length = 3x metres and breadth = 2x metres Then, 2 (3x + 2x) = 1600 or, x = 160 Length = 480 m and breadth = 320 m ∴ Area = (480 × 320) m2 = 153600 square metre
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