Luca has a 15% off discount card to use at the frozen yogurt place. If he buys $4.78 of frozen yogurt how much will he pay after the discount? please explain how you got your answer :)

Alcoa was $10.02 a share yesterday. today it is at $9.75 a share. if you own 50 shares, did ou have capital gain or loss ? how much of a gain or loss did you have ? express the capital gain/loss as a percent of the original price