Question

The Wood family and the Roberts family each used their sprinklers last summer. The water output rate for the Wood family's sprinkler was 25 L

per hour. The water output rate for the Roberts family's sprinkler was15 L
per hour. The families used their sprinklers for a combined total of 60
hours, resulting in a total water output of 1250 L. How long was each sprinkler used?

Answer 1

Wood family: 35 hours

Roberts family: 25 hours

Explanation:

Let w represent the number of hours the Woods family ran their sprinkler. Then 60-w is the number of hours the Roberts family ran theirs. The total water usage (in liters) was ...

25w + 15(60-w) = 1250

10w = 350

w = 35 . . . . . . Wood family time (hours)

60-w = 25 . . . Roberts family time (hours)

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Check

(35 h)·(25 L/h) + (25 h)·(15 L/h) = 875 L + 375 L = 1250 L . . . . answer checks OK