Question

The Rodriguez family and the Foster family each used their sprinklers last summer. The water output rate for the Rodriguez family's sprinkler was
40L
per hour. The water output rate for the Foster family's sprinkler was
25L
per hour. The families used their sprinklers for a combined total of
40
hours, resulting in a total water output of
1375L
. How long was each sprinkler used?

Answer 1

X+y=40
25x+40y=1375
25x+40(40-x)=1375
25x+1600-40x=1375
-15x=-225
X=15
15+y=40
Y=25
The Foster family used their sprinkler for 15 hours
The Rodriguez family used their sprinkler for 25 hours