Answer:
It is going 84.12s = 1 minute and 24.12 seconds to fill the tank.
Step-by-step explanation:
The filling time of a gas tank can be given by a first order function in this format:

In which
is the current amount of fuel in the tank(in L),
is the volume of the tank(in L),
is the discharge rate of the tank(in L/s) and t is the time in seconds.
Finding the values of the parameters:
The tank is completly empty, so
.
The volume of the tank is 14 gallons. However, the problem states that the volume of the tank is measured in liters.
Each gallon has 3.78L.
So 
The discharge rate for the gas is 38.0 l/min. However, the problem states that the discharge rate is in L/s. So, to find the value of r, we solve the following rule of three.
38 L - 60s
r L - 1s



Solving the equation:





It is going 84.12s = 1 minute and 24.12 seconds to fill the tank.