Question

the Green family and the Bryant family each used their sprinklers last summer. The water output rate for the Green family's sprinkler was 15L per hour. The water output rate for the Bryant family's sprinkler was 40L per hour. The families used their sprinklers for a combined total of 55 hours, resulting in a total 1450L water output of . How long was each sprinkler used?

Answer 1

green family=15n
n is number of hours
Bryant family= 40x
x is number of hours
15n+40x=1450L
n+x=55
use simultaneous equations
(15n+40x=1450)-(15n+15x=825)
25x=625
x=25hours
n=55-x
n=55-25=30hours