Im just going to try here..
First i'll work out how much water bottles are left
there are 4 cases and each contain 12 bottles
so thats 4 x 12 = 48
drink 3 bottles = 48 - 3 = 45
there are 45 bottles left
Now im going to use the expression she used
(12 - 3) x 4 = 36
Well then.. the answer is clearly wrong..
I would use:
4 x 12 - 3
so im sure the brackets are the mistake and that its the other way round..
so sorry if u find out its wrong.. its not often me seeing these type of questions.. ._.