Answer:it will take 2.5 hours for the hours of service to cost the same.
Explanation:
Let L represent the hours of service for which both babysitting services would cost the same.
Let x represent the cost of L hours when using the Babysitter's Block.
Let y represent the cost of L hours when using the Super Sitters.
The Babysitter's Block charges a rate of $15 an hour per child plus an initial fee of $25 per household. This means that the cost of L hours for the two children would be
x = 25 + 30L - - - - - - - - - - - -1
Super Sitters charges a flat rate of $20 an hour per child. This means that the total cost for L hours for the two children would be
y = 40L
To determine the the hours of service for which both babysitting services would cost the same, we would equate x to y. It becomes
25 + 30L = 40L
25 = 40L - 30L = 10L
L = 25/10 = 2.5 hours