With that added info, I have an idea. Make the minimum on all of the loans, or maybe just barely over the minimum (up to you personally), but focus on both the highest interest and smallest loan. 40K is a great salary, and you should be able to pay off that smallest loan within a year, even while paying extra on the highest interest loan.
So yes, that'll give you the bonus of lowering your mandatory monthly payment, but still be working on the mathematically best option. Then, yes, once that small one is off, still pretend your paying it, just push it towards the high interest loan. and then just keep snowballing. You'll be on the 5 year, instead of the 15 year plan.
Good luck!