Help me with this asap please

The final cost of a sale is determined by multiplying the price on the tag by 75%. which best describes the function that represents the situation?

Sam is a waiter at a local restaurant where he earns wages of $5 per hour sam figures that he also eams about $3 in tips for each person he serves sam works 6 hours on a particular day. if n represents the number of people sam serves that day, which of the following functions could sam use to figure ehis total earings for the do o a. en) = 30 o b. en) = 5n+ 18

Can someone explain to me how to do