Please help with my math homework

Trent wants to buy 2 packs of trading cards for 3 dollars each. the trading card packs that trent normally buys tend to come in packs of 6, 10, 12, or 15 cards. after selecting 2 packs, trent found that the first pack of cards cost 25 cents per card, and the second pack cost 30 cents per card. trent uses this information to write the equations below in order to compare c, the number of cards in each pack.

Just tell me how to set up the equation.

Eden has a part time job. she is paid ? 7.20 an hour the week she worked 18 and a half hours how much is she paid