Suppose you can work at most a total of 25 hours per week. Baby-sitting, x, pays $6 per hour and working at the grocery store, y, pays $9 per hour. You need to earn $171 a week to pay for your expenses.

y=7 number of hours at grocery store

x=18 number of hours at baby - sitting

Step-by-step explanation:

According to the information provided.

x is number of hours at baby - sitting

y is number of hours at grocery store

total number of hours worked

1) x+y = 25

total earn in a week

2) x*$6 + y * $9 = $171

from equation 1

x+y=25

x = 25-y

we place the above derived equation in equation 2

x*$6 + y * $9 = $171

(25-y) * $6 + y * $9 = $171

(25*6) - 6y + 9y = 171

150+3y=171

3y=171-150

3y=21

y=7 number of hours at grocery store

x = 25-y

x = 25-7

x=18 number of hours at baby - sitting