The Diaz family and the Johnson family each used their sprinklers last summer. The water output rate for the Diaz family's sprinkler was 40 L per hour. The water output rate for the Johnson family's sprinkler was 30 L per hour. The families used their sprinklers for a combined total of 50 hours, resulting in a total water output of 1800 L. How long was each sprinkler used?

Diaz family's sprinkler: x hours
Johnson family's sprinkler: x hours