Let x be the cost of one corsage, and y be the cost of one boutonniere, then we can set the following system of equations:
Solving the second equation for y, we get:
Substituting the above equation in the first one we get:
Solving for x, we get:
Substituting x=15 in the equation that we solved for y we get:
Answer: A corsage sells for $15, and a boutonniere sells for $28.