Final answer:
To calculate the time to fill a 30-gallon tank at a rate of 3.9 gallons per minute, divide the tank size by the discharge rate, which equals approximately 7.7 minutes or 7 1/2 minutes (answer choice A).
Step-by-step explanation:
The student asks how many minutes it will take to fill the 30-gallon tank of a pick-up truck if a gasoline pump dispenses about 3.9 gallons of gasoline per minute. To answer this, we must divide the total number of gallons needed by the rate at which the pump dispenses gasoline.
Time = Total Gallons / Gallons per Minute
Time = 30 gallons / 3.9 gallons per minute ≈ 7.7 minutes
Therefore, it will take a little over 7 and a half minutes to fill the tank, which corresponds to answer choice A) 7 1/2 minutes.