Please help me out 5x + 2 +3x + 5

How far could you drive on 50 gallons of gas

Clarence wants to buy a new car. he finds an ad for a car that costs 27,200 dollars. suppose his local sales tax is 7%. -how much would he have to pay? -what is the cost of the car including tax? -if clarence has 29,864 saved, can he pay cash to buy the car?

In a singing competition, there are 150 participants. at the end of each round, 40% of the participants are eliminated. how many participants are left after n rounds?