A department store is offering a coupon for 21% off for any purchases over $100.

Question

How much would you spend for a $100 purchase?
You would spend $100.

You would spend $79 on a purchase of $100.01
You would spend $79.8 on a purchase of $101.00
You would spend $87.69 on a purchase of $111.00

Construct a formula a piecewise functiom for the actual cost, C, of the purchase as a function of the original purchase price, P.

C=__?__,if 0 < P </ 100.

C=__?__, if P>100

Answer 1

C = 0.79P, P>100.