The base of a rectangular box measures $2 \mathrm{~cm}$ by $5 \mathrm{~cm}$. The volume of the box is $30 \mathrm{~cm}^{3}$. What is the height of the box?
(A) $1 \mathrm{~cm}$
(B) $2 \mathrm{~cm}$
(C) $3 \mathrm{~cm}$
(D) $4 \mathrm{~cm}$
(E) $5 \mathrm{~cm}$
The volume of a rectangular box equals the area of its base times its height.

Thus, the height equals the volume divided by the area of the base.

The area of the base of the given box is $2 \cdot 5=10 \mathrm{~cm}^{2}$.

Therefore, the height of the given box is $\frac{30}{10}=3 \mathrm{~cm}$.

ANswer: (C)