The Martinez family and Hayes family...

Question

The Martinez family and the Hayes family each used their sprinklers last summer. The Martinez family's sprinkler was used for 30 hours. The Hayes family's sprinkler was used for 15 hours. There was a combined total output of 1500 L of water. What was the water output rate for each sprinkler if the sum of the two rates was 65 L per hour? 

Answer 1

30M + 15H = 1500

M + H = 65

multiply both sides by 15 to get

15M + 15H = 15(65) = 975

subtract last from first equation to eliminate one variable

30M - 15M = 1500 - 975

15M = 525

divide both sides by 15

M = 525/15 = 35 L per hour for the Martinez family

H = 65 -35 = 30 L per hour for the Hayes family

check the answer

30(35) + 15(30) = 1050 + 450 = 1500