The question clearly sais the bank can borrow at Libor, so no need to think in terms of opportunity cost since there is plenty of more funding available to borrow at LIBOR. If the bank had scarce amount of money to lend that would be relevant, but the bank can borrow at LIBOR as the question states.
Also thinking in terms of opportunity of the money is not very appropriate, the bank can lend to different borrowers at different rates, I lend one of my clients at 9% and another at 3%, and I can find someone who is going down the drain that I can lend at 30% if I wanted to, should I use the 30% as the opportunity cost?
As far as why I am getting the charter, simply a matter of cost analysis, at this point the cost to me is a couple hundred hours I plan on putting for Level III, I just started, money and time for previous levels has already been paid so they are sunk costs.
Had I known all what I know about CFA when I started, it is not worth 900 hours and 3000 USD, however at this point it will cost me no money and only 200 hours of studying, the rest are sunk costs, and that is why i am doing it. No disrespect to any candidates or charterholders, many of whom are much smarter than me and are way ahead of me in life. However the majority just want to get a paper that sais they are charterholders without truely learning, and if you take a sample of those people 2 years after the exam and you compare it to sample of non charterholders with same experience, they are no better.
If I was answering this question at work i would simply solve for the irr
paid 475,000 at time 0, paid 100,000,000 at time 1, got 100,005,556 at time 2, the irr is my return