how long was each sprinkler used?

Question

The water output rate for the Nelson family’s sprinkler was 35L per hour. The water output rate for the Richardson family’s sprinkler was 40L per hour. The families used their sprinkle for a combined total of 40 hours, resulting in a total water output of 1475L how long was each sprinkler used?

Answer 1

Hi, Anastasia!

 

Okay, so let's call the number of hours the Nelson family's sprinkler ran = t

Then, since the combined time of the 2 families was 40 hours, then the Richardson's ran theirs 40 - t hours

So now we just solve the equation:

35t + 40(40-t) = 1475

35t + 1600 -40t = 1475

5t = 125

t = 25

 

So, the Nelsons ran their sprinkler for 25 hours

The Richardsons ran theirs for 15 hours