Answer:
Rodriguez family's sprinkler used for 40 hours
Perry family's sprinkler used for 15 hours.
Step-by-step explanation:
Let "x" be the number of hours Rodriguez family's sprinkler used and "y" be the number of hours Perry family's sprinkler used.
Now let's form two equations using the given information.
x + y = 55 ------------(1)
Using the output, we can form another equation.
15x + 20y = 900 -----(2)
Now we have to solve these two equations to find the number of hours each sprinkler used.
We can use substitution method to solve these two equations.
From the equation (1), we can write
x = 55 - y
Now plug in x = 55 - y in the equation (2), we get
15(55 - y) + 20y = 900
Using the distributive property a(b -c) = ab - ac, we get
15(55) - 15y + 20 y = 900
825 - 15y + 20y = 900
Simplifying the above equation, we get
5y = 900 - 825
5y = 75
Dividing both sides by 5, we get
y = 15
Now plug y = 15 in x = 55 - y to find the value of x.
x = 55 - 15
x = 40
So, Rodriguez family's sprinkler used for 40 hours
Perry family's sprinkler used for 15 hours.
