SOLUTION: The Stewart family and the James family each used their sprinklers last summer. The water output rate for the Stewart family's sprinkler was 35L per hour. The water output rate for

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: The Stewart family and the James family each used their sprinklers last summer. The water output rate for the Stewart family's sprinkler was 35L per hour. The water output rate for      Log On


   

Question 1111987: The Stewart family and the James family each used their sprinklers last summer. The water output rate for the Stewart family's sprinkler was 35L per hour. The water output rate for the James family's sprinkler was 30L per hour. The families used their sprinklers for a combined total of 45 hours, resulting in a total water output of 1500L. How long was each sprinkler used?
Stewart familys sprinkler:____hours
James familys sprinkler:____hours
Found 2 solutions by josgarithmetic, greenestamps:
Answer by josgarithmetic(39618) About Me  (Show Source):
You can put this solution on YOUR website!
FAMILY       RATE        TIME      VOLUME
Stewart      35          t          35t
James        30          45-t       30(45-t)
Total                    45         1500


highlight_green%2835t%2B30%2845-t%29=1500%29
7t%2B6%2845-t%29=300
highlight%28t=30%29------Stewart
highlight%2815%29--------James

Answer by greenestamps(13200) About Me  (Show Source):
You can put this solution on YOUR website!


If you don't need to use formal algebra to solve the problem, here is an easy way to get the answer to this kind of problem with a little mental arithmetic.

If all 45 hours of water used had been by the James family, the total water usage would have been 45*30 = 1350L -- 150L short of the actual total.

The Stewart family's sprinkler uses 5L more per hour than the James family's; to get those "extra" 150L of water usage, the number of hours the Stewart family's sprinkler had to be running is 150/5 = 30.

And that leaves 45-30 = 15 hours for the James family's sprinkler.