I need a clearer understanding of how to solve: To get free delivery, Alice needs to spend a minimum of $35.00 online at her favorite grocery store.  In her cart she has 1.5 pounds of chicken at $6.00 per pound, 1 pack of lettuce for $3.00, cherry tomatoes for $2.50, 4 sweet potatoes at $0.75 each, 2 heads of broccoli for $2.00 each and a pound of Brussel sprouts for $2.50.  How much more does she need to spend in order to get free delivery?