During the first six months of the year, the Montgomery’s monthly electric bills were $128.45, $131.50, $112.30, $96.25, $81.70, $71.70 How can the Montgomery’s find their average monthly electric bill for the first six months of the year

1. a music store marks up the instruments it sells by 30%. a. if the store bought a guitar for $45, what will be its store price? b. if the price tag on a trumpet says $104, how much did the store pay for it? c. if the store paid $75 for a clarinet and sold it for $100, did the store mark up the price by 30%?