Question

A diner makes vanilla milkshakes and chocolate milkshakes. The vanilla milkshake machine has a 400 cup capacity, and sells 15 cups per day. The chocolate milkshake machine has 280 cup capacity and sells 20 cups per day. Write an equation to show when the two machines will have the same amount of milkshake left. Use x as your variable

Answer 1

Let x represent the number of days since the machines started producing milkshakes.

The vanilla milkshake machine will have 400 cups - 15 cups/day * x days = 400 - 15x cups left.

The chocolate milkshake machine will have 280 cups - 20 cups/day * x days = 280 - 20x cups left.

Setting the two expressions equal to each other, we have:

400 - 15x = 280 - 20x.