Mixed Up?

A recipe calls for one can of drink mix for every 5 cans of water. You mix up two batches of the recipe and place them in two separate containers. Later, you realize that you will need a little more to drink so you decide to add just a little bit more to one of your containers. You add one more can of drink mix and one more can of water. Will the two recipes taste the same? What are two ways you could use to mathematically determine whether the recipes would taste the same?