She worked a total of 15 hours. If she makes $15 per hour tutoring and $9 per hour at the grocery store and made a total of $159 how many hours did she work at the grocery store

11 hours she worked at the grocery store

Step-by-step explanation:

assuming,

the number of hours worked at tutoring = x

the number of hours worked at grocery store = y

which means,

the amount she made at tutoring = x * $15

the amount she made at grocery store = y*$9

we have 2 equations

total number of hours

1) x+y = 15

total amount she earned

2) x * $15 + y * $9 = $159

From equation 1

x+y = 15

x=15-y

we replace this x value in equation 2

x * $15 + y * $9 = $159

(15-y) * $15 + y * $9 = $159

(15*15) - 15y+9y=159

225-6y=159

225-159=6y

66=6y

66/6=y

11=y the number of hours she worked at grocery store.

we place y=11 in our derived x equation

x=15-y

x=15-11

x=4 the number of hours she worked at tutoring.