If a quadrilateral is a parallelogram, then a) its opposite angles are supplementary. b) its consecutive sides are congruent. c) its consecutive angles are congruent. d) its consecutive angles are supplementary

The salesperson earns a 5% commission on the first $5,000 she has in sales. the salesperson earns a 7.5% commission on the amount of her sales that are greater than $5,000. this month the sales person had $8,000 in sales. what amount of commission, in dollars, did she earn?