Answer:
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
<em>total number of hours</em>
1) x+y= 15
<em>total amount she earned</em>
2) x* $15+ y* $9= $159
From equation 1
x+y= 15
x=15-y
<em>we replace this x value in equation 2</em>
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
<u>11=y</u> <em>the number of hours she worked at grocery store. </em>
<em>we place y=11 in our derived x equation</em>
x=15-y
x=15-11
<u><em>x=4 </em></u><em>the number of hours she worked at tutoring. </em>
4 / 0.80 = 12 / x...cross multiply
4x = 0.80 * 12
4x = 9.6
x = 9.6 / 4
x = 2.4.....12 apples cost $ 2.40
All work is show in the picture below.
