HELP NEEDED

PLEASE HELP ASAP

Twenty-five percent of the customers entering a grocery store between 5 p.m. and 7 p.m. use an express checkout. consider five randomly selected customers, and let x denote the number among the five who use the express checkout.

Ahigh definition tv cost $800 with a down payment of 2/5 of the cost. how much is left to pay, in dollars after the down payment has been made?

Iwant to know what 3g+5h+4g-2h is my teacher is too selfish to tell us