The water output rate for the Jackson family's sprinkler was 15L per hour. The water output rate for the Simmons family's sprinkler was 30L per hour. The families used their sprinklers for a combined total of 55L hours, resulting in a total water output of 1425L. How long was each sprinkler used?

Question

The water output rate for the Jackson family's sprinkler was 15L per hour. The water output rate for the Simmons family's sprinkler was 30L per hour. The families used their sprinklers for a combined total of 55L hours, resulting in a total water output of  1425L. How long was each sprinkler used?

artfis · Answer

What would be the formula? That's all I need.

anonymous · Answer

Can you come up with some variables first?

kropot72 · Answer

J = number of hours for Jackson's sprinkler
S = number of hours for Simmon's sprinkler
J + S = 55
Therefore S = 55 - J ......................(1)
15J + 30S = 1425 ..........................(2)
Now just substitute the value of S from equation (1) into equation (2) and solve to find J.

anonymous · Answer

Figure out what you want your variables to represent.

mathstudent55 · Answer

The Jackson family used x hours
The Simmons family used y hours

liters/hour times hours = liters used

Water used:
Jackson family: 15x
Simmons family: 30y
Total water used: 15x + 30y = 1425

Total time used:
x + y = 55

Solve system of equations:
15x + 30y = 1425
x + y = 55

artfis · Answer

Thanks I see that I tried to solve for y first, and it got all jacked up.

kropot72 · Answer

You're welcome :)