Part 1. Definition
In this task, you need to provide the correct option for a given problem on probability from the provided options.
Part 2. Example
Problem: in a throw of a coin find the probability of getting a tail ? 
Options: a ) 1 / 2 , b ) 1 / 3 , c ) 1 / 4 , d ) 2 / 5 , e ) 2 / 7
Answer: a
Explanation: "s = { h , t } e = { t } p ( e ) = 1 / 2 answer is a"
Part 3. Exercise
Problem: find the probability that a number selected from numbers 1 , 2 , 3 , . . . , 20 is a prime number , when each of the given numbers is equally likely to be selected ? 
Options: a ) 10 / 20 , b ) 1 / 20 , c ) 8 / 20 , d ) 3 / 20 , e ) 7 / 20
Answer:
c