Q7 PERCENTAGES

Let A and B be two solid spheres such that the surface area of B is 300% higher than the surface area of A. The volume of A is found to be k% lower than the volume of B. The value of k must be

a. 85.5

b. 92.5

c. 90.5

Surface area of sphere A (of radius a) is 4πa²

Surface area of sphere B (of radius b) is 4πb²

4π a²/4π b²=1/4 => a:b=1:2

Therefore, k = 7/8 100% = 87.5%

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