AMC12 2012 12A, Problem 3

A box $2$ centimeters high, $3$ centimeters wide, and $5$ centimeters long can hold $40$ grams of clay.  A second box with twice the height, three times the width, and the same length as the first box can hold $n$ grams of clay.  What is $n$?

Solution: The first box has volume $2\times3\times5=30\text{ cm}^3$, and the second has volume $(2\times2)\times(3\times3)\times(5)=180\text{ cm}^3$.  The second has a volume that is $6$ times greater, so it holds $6\times40=\fbox{240}$ grams.

Answer: 240