Mrs. Palmer bought one pair of goggles, one bathing suit, and one beach towel for each of her three daughters. Suppose she had $18 left after buying the swimming items. Write an equation to determine the amount Mrs. Palmer originally had to spend on each daughter.

Let a be the amount Mrs. Palmer had before she bought anything

let x be the price of a pair of goggles

let y be the price of a bathing suit

let z be the price of a beach towel

3x+3y+3z+$18=a

There needs to be 3 of each item because she has 3 daughters. She has $18 left after all the purchases meaning that it is part of all the money Mrs. Palmer had