Question

I need help on this question

Answer 1

First off, rewrite all of the fractions so that they have a common denominator.  That's 2/12, 2/12, and 4/12.  Adding these together, we get 8/12.  That's the probability of getting an A, B, or C — but not a D.  The chance of getting a D is represented by the remaining 4/12 — or 1/3.  

TIn short, the chance of rolling D is exactly 1/3.