A concession stand has crates of bottled water to sell at a sporting event. Each crate holds 48 bottled waters and costs the concession stand $9.20. If the concession stand wants to make exactly $34.00 profit per crate of bottled water, customers should be charged $ for each bottled water.

If a crate holds 48 bottles and you want to make exactly $34 on selling them, before you find out exactly how much to charge for each bottle, you have to subtract the amount you paid for the crate from the profit. The unknown here is the cost per bottle that you have to make in order to reach your goal of $34. If you have 48 bottles of water and you want to know how much to charge PER bottle, the algebraic expression for that would be 48x. Now from that profit of 48x you need to subtract the $9.20 and set it equal to what you'd like to earn:

48x - 9.20 = 34.00

Solve this by adding 9.2 to both sides, and then dividing by 48. That gives you a cost per bottle of 90 cents. Plug .90 in for x in the equation above and see that the left side does indeed equal the right side.