Question

An oil company fills 1 over 12 of a tank in 1 over 3 hour. At this rate, which expression can be used to determine how long will it take for the tank to fill completely? 1 over 12 ⋅ 3 hours 1 over 3 ⋅ 12 hours 1 over 3 ⋅ 1 over 12 hours 3 ⋅ 12 hours

Answer 1

Don't let fractions fool you.

$\frac{1}{12}$ of a tank in $\frac{1}{3}$ an hour is equal to:
1/12 of a tank in 20 minutes.

Thus we know in an hour, an oil company can fill 3/12 of a tank (60 minutes in an hour).

3 x 4 = 12, and 12/12 = 1(a whole tank), so we multiply 1 (hour) by 4.

Our answer is that it takes 4 hours to fill a tank.