Please help, it’s due in 10 minutes!!

There were 816 people at a concert when a band started to play. after each song, only half the people stayed to hear the next song. how many people were left at the concert after x songs? write a function to represent this scenario.

An 18% discount on a watch saved a shopper $72. find the price of the watch before the discount

The mass of a marine organism, in pounds, p years after it is born is given by the polynomial function r(p) = -4p2 + 300p. find the mass when p = 20 years.