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What percentage increase in the radius of a sphere will c...

What percentage increase in the radius of a sphere will cause its volume to increase by 45%?

A.

13%

B.

15%

C.

23%

D.

25%

Correct answer is A

Let the original volume be V with radius r.

V=43πr3

45% increased volume = 145%V. 

Let the %age increase in radius = m%r

145100V=43π(mr100)3

1.45V=(43πr3)(m100)3

1.45V=V(m100)3

1.45×106=m3

m=31.45×106=113.2

\approxeq 13%