Once you know how many minutes are in an hour, multiply that by 12 gallons per minute to find how many gallons the pump moves in one hour.

You’re given that 1 cubic foot equals 7.5 gallons. If you know the total gallons, should you multiply or divide by 7.5 to find how many cubic feet that is?

Make sure your final units are cubic feet, not gallons. If you still have gallons, you haven’t used the 7.5 gallons per cubic foot conversion yet.

In a new expression line, type (12*60)/7.5. Desmos will show the value of this expression; that value is the number of cubic feet of water pumped in one hour.

The pump moves water at $12$ gallons per minute, and we want cubic feet in one hour.

Plan:

• First, convert 1 hour into minutes.
• Use the rate (gallons per minute) to find how many gallons are pumped in that hour.
• Then convert that number of gallons into cubic feet using $1$ cubic foot $=7.5$ gallons.

There are $60$ minutes in one hour.

Use the rate $12$ gallons per minute:

So, the pump moves $720$ gallons in one hour.

We know $1$ cubic foot $= 7.5$ gallons.

To change gallons to cubic feet, divide the number of gallons by $7.5$ (because each cubic foot contains $7.5$ gallons):

Here, the number of gallons is $720$, so we need to calculate $720 \div 7.5$.

Now do the division:

So the pump moves $96$ cubic feet of water in one hour. The correct answer choice is C) 96.