The time t (in minutes) required to empty a tank of wastewater varies inversely with the rate r (in gallons per minute) of pumping. The constant of variation is 56. Find the time it will take to empty the tank when the rate is 4 gal/min.

A. 52 minutes

B. 0.07 minutes

C. 224 minutes

D. 14 minutes

Correct option: D - > 14 minutes

Step-by-step explanation:

The meaning of the constant of variation for a inversely proportion is that the product of one variable by the other one will always be that constant value. That is, if we multiply the time t in minutes by the rate r in gallons per minute, we must find 56 as the result.

So if we want to find the time when the rate is 4 gal/min, we have:

t * r = 56

t * 4 = 56

t = 56 / 4 = 14 minutes

Correct option: D.