5) At the beginning of the week you have $7.50 in your lunch account. After buying 4 lunches for the same price, your account is now -$3.70. How much did each lunch cost?

step-by-step explanation:

the multiplicative inverse of a fraction a/b is b/a. for the multiplicative inverse of a real number, divide 1 by the number. for example, the reciprocal of 5 is one fifth 1/5 or 0.2, and the reciprocal of 0.25 is 1 divided by 0.25, or 4.