You are going to add the two fractions and but first you need to have the same denominator so you have 1/6 then 1/3 converts to 2/6 then you add then together which simplifies to 1/2 then u subtract it by one whole.
So basically what this is trying to tell you is are they mutiples / equal to each other, also a rule. Its A. because 25 x 2 = 50, then 50 x 2 = 100 and so on.
