Answer:
(a) 
(b) 7 hours.
Step-by-step explanation:
(a) Let x be the number of hours and y is the total cost.
We have been given that Beatrice and her friends charge $8 per hour of babysitting, so the charges for x hours of babysitting will be 8x.
As they also charge a mandatory $5 per day fee for each child for snacks, so the total charges for babysit each day will be charges for x hours of babysitting plus mandatory charge.
We can represent this information in an equation as:

Therefore, the equation
represents the total cost of using Beatrice’s babysitting service each day.
(b) To find the number of hours Beatrice babysit the daughter, we will substitute y = 61 in our equation and solve for x.

Let us subtract 5 from both sides of our equation.


Let us divide both sides of our equation by 8.


Therefore, Beatrice babysit 7 hours the daughter.
Expression for part c is missing.