Problem Solving

Coins are dropped into a toll box so that the box is being filled at the rate of approximately 2 cubic feet per hour. If the empty rectangular box is 4 feet long, 4 feet wide, and 3 feet deep, approximately how many hours does it take to fill the box?

A) 4
B) 8
C) 16
D) 24
E) 48

[spoiler]OA=D[/spoiler]

Source: Official Guide

Let the volume of the cube be \(V\)

Let the rate of filling it be \(r\)

So, time taken to fill the box will be \(\frac{V}{r}\)

$$V\ =\ 4\ \cdot\ 4\ \cdot\ 3\ =\ 48$$ $$r\ =\ 2$$ $$\frac{V}{r}\ =\ \frac{48}{2}\ =\ 24$$ D