If you are rolling a single six sided die numbered 1-6, you find that only 1,2,4, and 5 are factors of 20. Now the theoretical probability of an event is the ratio comparing the number of desired outcomes to the total outcomes possible.
In this case: we have 4 desired outcomes out of a total 6 outcomes possible with a single roll the die.. therefore, the probability you seek is or approximately 67%.
The answer is B because you will cancel the x^5 part on top and bottom and the numerator left 6^3 and denominator left 6 6^3=216divid by 6 you will get 36