A water tank has a capacity of 4000 gallons. Mack connects a pipe to the tank that fills the tank with water at the rate of 10 gallons per hour. How long will it take to fill the tank to 3/4 of its capacity?
3/4 of the water tank is 3/4*4000 = 
<gadget id="calculator">3/4*4000</gadget>
<output>3_000</output>
3000.
If the pipe fills the tank with water at the rate of 10 gallons per hour, it will take 3000/10 = 
<gadget id="calculator">3000/10</gadget>
<output>300</output>
300 hours to fill the tank to 3/4 of its capacity.

<result>300</result>