Question

A department store is offering a coupon for 28 ⁢  % off for any purchases over dollar-sign Baseline 100. Construct a piecewise function for the actual cost, C, of the purchase as a function of the original purchase price, P.

When 0<P</100 I got C=P. But I can't seem to get the formula for when P>100.

Answer 1

for 100 < P,
C(P) = 100 + 0.72(P-100)
or
C(P) = P - 0.28(P-100)