Generally, evident truths do not require mathematical confirmation, but it is pleasant to run into a strict proof time to time. Here is a recent example (reportedly, due to Rob Howard of Next Level Systems).
It is well known that "Knowledge is Power", and "Time is Money". In the algebraic form,
On the other hand, power is work per unit time, i.e.K = P, T = M. (1)
Plugging Eqs. (1) into Eq. (2), and solving for M, we getP = W/T. (2)
Thus the more knowledge the less money (at fixed total work), in good correspondence with recent experimental observations. Keep telling your students to study hard, friends.M = W/K.