Invitations cost $6 for a pack of 5. Lori gives the cashier $50 to buy invitations and gets $8 in change. How many packs of invitations does Lori buy?

35

Explanation:

Since Lori gives the cashier $50 to buy invitations and gets $8 in change, thus means that the amount spent on invitations = $50 - $8 = $42

Since he spent $42 and the invitations cost $6 for a pack of 5, the packs of invitations that he bought would be:

= ($42/$6) × 5

= 7 × 5

= 35 packs of invitation