An ice cream shop makes Vanella and chocolate ice cream. The vanella ice cream machine has a 180-cup capacity, and it sells 20 cups per day. The chocolate ice cream machine has a 140-cup capacity, and sells 16 cups per day. Write and solve an equation to show when the two machines will have the same amount of ice cream left?

Let x be the number of days it takes for the two machines to have the same amount of ice cream left.

The amount of vanella ice cream left after x days is 180 - 20x cups.

The amount of chocolate ice cream left after x days is 140 - 16x cups.

Setting these two expressions equal to each other:

180 - 20x = 140 - 16x

4x = 40

x = 10

Therefore, it will take 10 days for the two machines to have the same amount of ice cream left.