Stacy goes to the county fair with her friends. The total cost of ride tickets is given by the equation c = 3.5t, where c is the total cost of tickets and t is the number of tickets.

If Stacy bought 15 tickets, she would spend $

c=3.5t

c=3.5(15)
c=52.5
So, Stacy would spend $52.50. Answer: \boxed{52.5}.

To find out how much Stacy would spend if she bought 15 tickets, we can substitute t = 15 into the equation c = 3.5t.

c = 3.5(15)

c = 52.5

Therefore, Stacy would spend $52.50 if she bought 15 tickets.

To find out how much Stacy would spend if she bought 15 tickets, we can substitute the value of t = 15 into the equation c = 3.5t.

c = 3.5t

c = 3.5 * 15

c = 52.5

Therefore, if Stacy bought 15 tickets, she would spend $52.5.