The diameter of the average cell in the human body is 1 x 10^-5 meters. the diameter of a grain of sand is about 2 x 10^-4 meters. the diameter of a human hair is about 0.25 meters. explain your answer theres part a, b,

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