Answer:
Bailey family's sprinkler was used for 35 hours and Harris family's sprinkler was used for 20 hours.
Step-by-step explanation:
Set up a system of equations.
Let be "b" the time Bailey family's sprinkler was used and "h" the time Harris family's sprinkler was used.
Then:
[tex]\left \{ {{b+h=55} \atop {15b+40h= 1,325}} \right.[/tex]
You can use the Elimination method. Multiply the first equation by -15, then add both equations and solve for "h":
[tex]\left \{ {{-15b-15h=-825} \atop {15b+40h= 1,325}} \right.\\.............................\\25h=500\\\\h=\frac{500}{25}\\\\h=20[/tex]
Substitute [tex]h=20[/tex] into an original equation and solve for "b":
[tex]b+20=55\\\\b=55-20\\\\b=35[/tex]