Write a system of equations to describe the situation below, solve using substitution, and fill in the blanks. Reba plans to attend the Union County Fair and is trying to decide what would be a better deal. She can pay $30 for unlimited rides, or she can pay $18 for admission plus $2 per ride. If Reba goes on a certain number of rides, the two options wind up costing her the same amount. What is that cost? How many rides is that?

It will cost Reba $ _ for both options if she goes on _ rides.