12 bottles will be needed for a group that size
I just wrote out all the possible choices and of the 36 choices, 27 of them had a product that was even. I don't remember the shortcut to this, but I just wrote out 1*1, 1*2, 1*3, etc.
Well, it is bass times height divided by two
X=1
because you would add two to the other side and have 2x=2 divide by 2 and you would be left with x=1