I personally do not know what “t” stands for, but I can help you with the process. 3 t has to be converted into lbs(pounds). You have to change that unit of measurement into lbs because the answer wants it in lbs. So if you know what “t” stands for just convert it into lbs with a calculator if you can. I tried searching up what “t” stands for, but I couldn’t figure out if it was tsp or tbs. So after you can do that conversation you have to subtract 3 t = ? lbs - 81 lbs. I really hope this helped. Yeah I agree this was a tricky question.