Hannah buys 3 packs of 36 exposure films and 2 packages of 24 exposure films. she uses 8 rolls of film. how many rolls does she have left?

Well that's easy. You see first you multiply 3x36 then you multiply 2x24. Now you want to to add this two numbers. Lastly, you subtract 8 from your answer. Hope this helped

Whose mistake? can you give more details to what the question is asking?