7.In one cycle, an engine burning a mixture of air and methanol (methyl alcohol) absorbs 525 J and expels 415 J. What is the engine’s efficiency?

Answer 1

I am not sure what you mean by expel
If you mean does 415 J of work then
100 (415/525)
If you mean 415 was spewed out in the exhaust and
525 - 415 = 110 J was used to lift the load then
100 (110/525)