Bailey buys two shirts. The blue shirt costs $13, which is $2.50 more than the price of the red shirt. What is the cost of the red shirt? Write and solve an equation to find the answer, using r to represent the cost of the red shirt.
Its 10.50 dollars
The cost of the red shirt is r.
The cost of the blue shirt is r + $2.50.
The total cost of the two shirts is r + r + $2.50 = $13.
Combining like terms, we get 2r + $2.50 = $13.
Subtracting $2.50 from both sides, we get 2r = $10.50.
Dividing both sides by 2, we get r = $5.25.
The cost of the red shirt is $5.25. Answer: \boxed{5.25}.