List these fractions form greasiest to least

Which shows the correct solution of the equation 1/2a+2/3b=50, when b=30?

If the ratio of sum of the first m and n terms of an ap is m2 : n2 , show that the ratio of its mth and nth terms is (2m − 1) : (2n − 1).

D. in a discrete probability distribution, the sum of the probabilities for the discrete variables will be > 1. true or false