Mia was getting ready to go back to school. She purchased 7 pens and a binder that cost $1.25. She spent a total of $7.90. How much did each pen cost?

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