Question

At a gas station, it takes 14 seconds to pump 2 gallons of gas. if the amount of gasoline pumped varies directly with time, how long does it take to fill an empty 12-gallon tank

1. 84 seconds
2. 90 seconds
3. 70 seconds
4. 28 seconds

Answer 1

If it takes 14 seconds to pump 2 gallons then it takes 14/2=7 seconds to pump 1 gallon, so it takes 7*12=84 seconds to pump 12 gallons. So the answer is 1.

Answer 2

See below:

Explanation:

If we do this, we know that 2 gallons takes 14 seconds. (2:14)

Based on that data, we can know that 1 gallon takes 7 seconds. (1:7)

-> 2/14 = 1/7

Now we can multiply by 12 to get 12 gallons on one side.

What we do on one side has to happen to the other side.

So, 12 gallons * 1 gallons = 12 gallons and 12 gallons * 7 gallons = 84 gallons.

So the final answer is 85 gallons,