Noah bought 15 baseball cards for $9.00. Assuming that each baseball card costs the same amount, answer the following questions. How much will 30 baseball cards cost?

$18.00

Step-by-step explanation:

Because you know that 15 baseball cards costs 9.00.  30 is 2 15s added together.  So you will do 9.00+9.00 in order to get the amount of money it needs.  Double the baseball cards cost double the money.

Hope this helps.  Please give brainliest.

you need a common difference between consecutive terms to be constant, like 1,2,3,4 or 2,4,6,8, or 1,3,6,9