Can anyone help make this math make sense?
I'm studying for a seal test, and this question doesn't seem to be mathing to me:
"Calculate the boiler efficiency using the steam generated vs. the fuel consumed method, if a coal plant consumed 1,363,000,000 lbs of 13,260 Btu/lb coal and generated 6,400,000 Ib of steam for a month of operation. (Feedwater temp. 208 F, Steam conditions: 179 psig and superheated to 520 F with a heat content of 1,280.4 Btu/lb.) "
86.3%
82.6%
78.3%
74.6%
Google AI (I know AI isn't that reliable) seems to use the same formulas I would, and everything makes sense until the end, where it just glosses over the fact that those numbers don't work out that way, and gives the same answer the practice test says is correct. I'm trying to overcome the temptation to just memorize the answers, and try to actually learn what it is I'm saying. The test says the correct answer is 78.3%...
Any help in understanding this, or what I'm doing wrong would be a great help.