college math
posted by Samantha .
The ratio of soda to diet soda in Bill's Supermarket is 8 to 9. If a person counted 72 bottles of soda, how many bottles of diet soda are there?

S = # of soda cans = 72
D = # of diet soda cans
S/D = 8/9 = 72/D
D = (9/8)*72 = 81