Help please its for a test

How far could you drive on 50 gallons of gas

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

At a book fair, joe bought 24 books at 3 for $5 and had $2 left. how much money did he have at first?