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The Young family and the Kim family each used their sprinklers last summer.
The Young family's sprinkler was used for 40 hours.
The Kim family's sprinkler was used for 25 hours.
There was a combined total output of 2075L of water.
What was the water output rate for each sprinkler if the sum of the two rates was 65L per hour?
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Let Y be the water output rate for Y family;
Let K be the water output rate for K family.
Write equations as you read the problem
Y + K = 65 (1) (counting the output rates)
40Y + 25K = 2075 (2) (counting total combined output)
To solve the system, from eq(1) exress K = 65 - Y and substitute it into eq(2)
40Y + 25*(65-Y) = 2075.
Simplify and find Y
40Y - 25Y = 2075 - 25*65
15Y = 450
Y = 450/15 = 30.
ANSWER. The output rate is 30 L/h for Y family and 65-30 = 35 L/h for K family.
Solved.