In a certain chemical, the ratio of zinc to copper is 3 to 14. A jar of the chemical contains 280 grams of copper. How many grams of zinc does it contain?

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