Question

Not sure of the answer doesn’t make sense to me

Answer 1

$27$

1) Consider that:

$r_A=3r_B$

The best way to tackle questions like this is to give them actual measures. So, say the radius of sphere A is 3 units and the radius of sphere B is 1.

2) We need to keep in mind that the Volume of the sphere is given by:

$\begin{gathered} V=\frac{4}{3}\cdot\pi\cdot r^3 \\ V_A=\frac{4}{3}\cdot\pi\cdot(3)^3 \\ V_A=36\pi \\ V_B=\frac{4}{3}\cdot\pi\cdot(1)^3 \\ V_B=\frac{4}{3}\pi \end{gathered}$

So now, let's divide one by another to get how many times the Volume of sphere A is larger than sphere B

$\frac{V_A}{V_B}=\frac{36\pi}{\frac{4}{3}\pi}=36\times\frac{3}{4}=27$

Note that we could cancel pi