please answer!!!!!!
( 10 points)

Answer:
the answer would be 20/b
Step-by-step explanation:
if 3 was 5 dollars
6 was 10 dollars
and 9 was 15 dollars you are counting by 5
5, 10 ,15, 20 ,25 ,30 etc.
3 6 9 12 15 18 etc.
please give brianlist.!!