A symbol used to name one or more parts of a whole or asset or a location on the number line is a

Which of the following is most likely the next step in the series? a3z, b6y, c9x, d12w, е15v, f18u

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.

When you answer this can you explain