Haley pays a monthly fee of 20$ for her cell phone and then pays 5 cents for every minute used. the cost of haley's cell phone bill can be expressed by the function c(m)=0.5+20, where m is the number of minutes used what are the domain and range of the function c(m)

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%?