75/200 movie goers watching 3D were students. 37.5% were students
50/100 movie goers watching 2D were students. 50% were students.
They both don't have the same number of zero as the answer because you are doing 40x500 which 20000 and 4x600 which is 2400
Notice the picture below
just use the pythagorean theorem to ge the diagonal