Write a number y divided by 6 as an expression

If the dimensions of a rectangular prism are 5 ft x 3.5 ft x 2 ſt, what is the surface area?

Jada has a meal in a restaurant she adds up the prices listed on the menu for everything they ordered and gets a subtotal of $42.00. when the check comes, it says they also need to pay $3.99 in sales tax. what percentage of the subtotal is the sales tax

I'm confused on this could anyone me and show me what i need to do to solve it.