Answer:
The amount Roberta makes an hour is $119.5
Step-by-step explanation:
Let the number Roberta makes be x hours.
Amount earned in x hours shift - 9*x + 12.5% of the amount of jewelry sold.
Number of hours worked by Roberta if 9 hours and jewelry worth $380 is sold by her.
Substituting the values:
Amount earned in an 8 hour shift = 9*8 + 12.5% od 380
= 72 + 0.125 * 380 (12.5% = 0.125)
= 12 + 47.5
= 119.5