Bruce Wayne is selling Shark Repellant Bat Spray at a stand. The fixed cost of running the stand per day is $30. Each bottle costs him $5 to produce....

Bruce Wayne is selling Shark Repellant Bat Spray at a stand. The fixed cost of running the stand per day is $30. Each bottle costs him $5 to produce. By his friend Alfred's calculations, he will be able to sell 10 bottles per day. Assuming Alfred's calculations are correct, what is the smallest price that Bruce should set for his Shark Repellant Bat Spray to break even?