Putting My Nerd Hat On
Look at all those itty-bitty numbers. And just one variable. How tough can it be?
UPDATE: After drinking a couple cups of coffee and shaking loose the cranial cobwebs, I sat down and started from scratch. Ended up taking me maybe an hour to get it, without having to use a calculator (unless I wanted the answer in decimal form).
I'll post the solution in a minute. There was a typo on it.