Question

A firkin is an old British unit of volume equal to 9 gal. lons. How many cubic meters are there in 12.4 firkins?

Answer 1

`0.4224" m"^3`.

Explanation:

One gallon is `3.785` liters. One liter is one cubic decimeter (deci is the old metric prefix for one tenth), thus `0.001` cubic meter. Then

`(12.4" firkin")({9 " gal"}/"firkin")({3.785" L"}/"gal")({0.001" m"^3}/"L")=0.4224" m"^3`

The numbers `9` and `12.4` are treated as exact for this problem, but the conversion factor of `3.785` liters per gallon is rounded to four significant digits. So the final answer is likewise rounded.