Question

A small tank, which initially contained 150 gallons of water, is being drained at a constant rate of 2 gallons per minute. In how many minutes will the tank be half- empty?

Answer 1

You could set this up as an equation

2x= gpm-gallons per min at which the tank is being drained.
150 being the initial amount

2x-150

Since the question is asking how long it’ll take for the take to be half empty take the initial amount and divide it by 2.
2x-75
Add 75 to the right
2x=75
X=37.5

Answer 2

The tank will be half empty after 37.5 min, or 37 min 30 sec.

Explanation:

"Half empty" means that the tank still contains 75 gallons of water.

75 gallons

---------------- = 37.5 min

2 gal/min

The tank will be half empty after 37.5 min, or 37 min 30 sec.