Question

The Pham family and the Morgan family each used their sprinklers last summer. The water output rate for the Pham family's sprinkler was 25L per hour. The water output rate for the Morgan family's sprinkler was 35L per hour. The families used their sprinklers for a combined 65total of hours, resulting in a total water output of 1975L . How long was each sprinkler used?

Answer 1

Answer:

Pham Family = 30 hours

Morgan Family = 35 hours

Step-by-step explanation:

Step 1 Deriving the equation

Let the duration in hours of Pham Family sprinkler = "x"

Let the duration in hours  of Morgan Family = "y"

Total combined duration = 65 hours provided.

That is:

x + y = 65                               Equation 1

Pham's sprinkler capacity = 25 litre per hour

Total water through this = 25 litre per hour for "x" hours = 25x

Morgan's sprinkler capacity = 35 litre per hour

Total water through this = 35 litre per hour for "y" hours = 35y

Now, provided

Total water output from both = 1,975 litre

That means

25x + 35y = 1,975                   Equation 2

Step 2 Solving the equation

Let us multiply equation 1 with 25

We have

25x + 25y = 65 $\times$ 25

25x + 25y = 1,625                       Revised Equation 1

Subtracting revised equation 1 from equation 2 we have:

(25x - 25x) + (35y - 25y) = (1,975 - 1,625)

0 + 10y = 350

y = 350/10 = 35

Since y = 35

Putting value of y in original equation 1 we have

x + 35 = 65

x = 65 - 35 = 30

Thus, Total Sprinkler hours of Pham = 30

Total Sprinkler hours of Morgan = 35