HELP ME PLEASE I GIVE BRAINLY

Shern goes to the BX with $21. She buys a gift for her mom that costs $9.25. She also needs to make sure that she has $3.50 left when she leaves the BX to buy lunch the next day. She sees that bags of Skittles are on sale for $0.40 each. How many bags can she buy to have as many bags as possible. Write and solve an inequality to represent the situation. Show your work.