Respuesta :

Answer:

$18

Step-by-step explanation:

15*2=30

So we need to multiply 9.00 by 2 too!

9*2=18

Keep up the good work!

We know that

15 baseball cards cots $9.00

So in order to get 30 all we need to do is times what we know by 2

15x2 = 30

9 x 2 = 18

Therefore, 30 baseball cards will cost $18.00