This was a problem I did with my students in Calculus 151c (that's differential calculus at OSU). The students seemed to like it... It's a fairly basic rate problem, I think it's a really good problem because it ties together the relationship between rates, derivatives, and integrals. Here goes...

The Beer Bong Problem

Jim is a college student, and like many others, he likes to spend his weekend drinking at parties. At the party in question, Jim is invited to drink from a beer bong, and he accepts. Before he begins, the bong is filled with 12 ounces of beer. Jim can drink beer at an initial rate of 1.5 ounces per second. However, as he drinks and runs out of breath, the rate at which he can drink decreases by a constant factor. Of course, Jim's friends will be adding more beer to the bong at a rate of 2 ounces per second. Assume the bong can hold a maximum of 22 ounces of beer.

a) Give an equation for the amount of beer in the bong at any time t
b) Assuming the constant factor of decreasing drinking rate is .1 ounces per second, will the bong overflow before Jim is finished drinking?
c) Find a constat that that will leave the bong empty just as Jim is finished drinking (to minimize waste of beer)

Note: I'll post the solution to this tomorrow, time for bed now :)