I'm an engineer who went back to school and obtained a masters in finance and economics when in my forties. Much of my career to that point had been in economics and corporate finance so the masters level stuff seemed easy.

Now, if I had to recall that V=IR stuff or figure out the difference between entropy and enthalpy I'd be in trouble. I actually made an "A" in thermodynamics, but that was only after I had made a "C" in physical chemistery.