Answer:
$35 bonus for each sale.
Step-by-step explanation:
9*(bonus) + $50 = (Payment for week 1)
10*(bonus) + $15 = (payment for week2)
Find how much the bonus was.
Both payments for each week were the same so
9*B + 50 = 10*B + 15
50 - 15 = 10B - 9B
$35 = B