I didn't use it in the grocery store

Remember when math class was horrible and you would ask the teacher, "When am I ever going to use this?" The response was always, "At the grocery store!" Admittedly, I took math classes for far too long but I will say that this line of reasoning dried up pretty quickly. When suffering through a differential equations class in college I certainly couldn't come up with any "real life" scenarios in which I could apply those skills I was learning. Now I know that is just because I was a naive college student.

With a little more life under my belt, I have found the application. The problem they always made you solve in that class had to do with some giant vat of water with one pipe for water to flow out of and one pipe for water to flow into the vat. The questions were always something like, "If the vat of water is full and the rate of water flowing out is blahblah then at what rate does the water need to flow in for the vat to neither empty nor overflow in an hour?"

At the time I thought that question was for future engineers in food plants so that they could ensure no giant vats of chemical ingredients ever emptied to the point that the dead rats were visible to prompt an inspection from the FDA. Now I know it was actually meant for moms who want to load the dishwasher, so I ask:

If the dishwasher is empty and the sink is full of dirty dishes. How fast must you load the dishes, given a rate of spoon and sippy cup removal of 1 per minute by one 9 month old, in order to be able to run a full load within a reasonable time frame?

The answer is cheat and give him an entire shelf of sippy cups to remove!