J. D. is saving up to buy an ipad Pro. It is advertised on the web site for $799. He has $279 saved. To make money, he feeds his grandparents cats when they go away. His grandmother pays him $5.00 a day. How many days will he need to take care of his grandparents' cats in order to have enough money to buy the ipad? His parents said they will pay the sales tax. Define your variable