Question

The Roberts family and Robinson family each used their sprinklers last summer. The water output rate for the Roberts family's sprinkler was 25 L per hour. the water output rate for the Robinsons family's sprinkler was 30 L per hour. The families used their sprinklers for a combined total of 50 hours, resulting in a total water output of 1325 L. How long was each sprinkler used?

Answer 1

Step-by-step explanation:

Let x be the number of hours Roberts family used their sprinkler.

Let y be the number of hours the Robinsons family used their sprinkler.

We're told that the two families used their sprinklers for a combined total of 50 hours, our equation will now be;

`x+y=50`

We're also told that the water output rate for the Roberts family's sprinkler was 25 L per hour and the water output rate for the Robinsons family's sprinkler was 30 L per hour resulting in a total water output of 1325 L, our 2nd equation will now be;

`25x+30y=1325`

Let's multiply the 1st equation by 25;

`25x+25y=1250`

If we subtract the 3rd equation from the 2nd equation, we'll have;

`\begin{gathered} 5y=75 \\ y=(75)/(5)=15 \end{gathered}`

Since y = 15, let's put this into the