The radius of a sphere is reduced by 40%. By what percent will its volume decrease?
A. 60%
B. 64%
C. 72.5%
D. 78.4%
Answer: Option D
Solution (By Examveda Team)
$$ - 40\% \to \frac{{ - 2}}{5}$$
$$\eqalign{ & {\text{Decrease }}\% = \frac{{98}}{{125}} \times 100 \cr & = \frac{{98 \times 4}}{5} \cr & = \frac{{392}}{5} \cr & = 78.4\% \cr} $$
This Question Belongs to Arithmetic Ability >> Mensuration 3D
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