Question

The Escobar family and the Johnson family each used their sprinklers last month. The water output rate forthe Escobar family's sprinkler was 20 gallons per hour. The water output rate for the Johnson family's sprinkler was40 gallons per hour. The families used their sprinklers for a combined total of 32 hours, resulting in a total wateroutput of 960 gallons. How many hours was each family’s sprinkler used?

Answer 1

J = 32

E = 0

Explanation:

E is the number of hours for the Escobar family

J is the number of hours for the Johnson family

E + J = 32

E * 20 + J * 30 = 960

Multiply the first equation by -20 so we can use elimination

-20 E -20 J = -640

Add this to the second equation

E * 20 + J * 30 = 960

-20 E -20 J = -640

---------------------------------

10 J = 320

Divide by 10

J = 32

Now find E

E + J = 32

E + 32 = 32

E = 0