Quadratic Mathematics.

It's a trick question, the answer is actually 2.

She used 12 cups of flour.

Make a proportion to where 8/8 equals 32.
3/8 equals ?/32
Then cross multiply and divide.
32 x 3 = 96
96/8 = 12

You can also think of it like this. What number times 8 will get you 32?
Well that’s 4.
So 3 x 4 = 12
Since they are proportions of each other what the bottom is multiplied the top must be as well