Roberta makes a $9 an hour plus a 12.5% commission selling jewelry how much does she earn on a 8 hour shift which she sells $380 worth of jewelry

The amount Roberta makes an hour is $119.5

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