500
Melanie received 2 boxes of banana muffin mix. Each box holds 9 packages on mix. On Monday, Melanie sold 4 packages of mix. On Tuesday, she sold 7 packages of mix, and on Wednesday, she sold 3 more of mix. If Melanie sells all of the mix, how many packages of mix will she have to sell on Thursday?
She will need to sell 4 packages.