If the radius of a sphere is doubled, how many times does its volume become? · ABC26GN5000
Subject: General Aptitude · Chapter: Volume and Surface Area · Exam: R.R.B., 2006 2008
If the radius of a sphere is doubled, how many times does its volume become?
(a)2 times
(b)4 times
(c)6 times
(d)8 times
Answer
Answer (as printed): D
Explanation
Let the original radius be $r$. Then, original volume $=\frac{4}{3} \pi r^{3}$. $$\text { New } \text { radius }=2 r \text {. }$$ ∴ New volume $=\frac{4}{3} \pi(2 r)^{3}=8 \times \frac{4}{3} \pi r^{3}=8 \times$ original volume.
Explanation as extracted from the printed page; notation may be imperfect.