If a you have a 20% discount and u have $75 how much will u spend

Cal's go cart has a gas tank with the dimensions shown below. he uses a gas can that holds 11 gallon of gas, to fill the go cart tank. 11 gallon = 231 inches^3 how many full gas cans will it take to fill the go cart's gas tank?

Alex measured the length of an item to be 3.7 cm. the actual length is 3.5 cm. what is alex’s percent error?

Travis and paula went to lunch.travis ordered a sandwich for $7.50 and paula ordered a burger for $5.25.after lunch,they left a 15% tip for the waiter.how many money did they spend altogether?