Question

In a group of 20 persons, there are 5 graduates. If 3 persons are selected at random from the group, the probability that all the graduates is _____.

• A. 1/120
• B. 15/108
• C. 1/114
• D. 5/114

Answer 1

The correct option is C 1/114

Probability shows the relationship between two variables in the form of ratio, percentage or proportion where there the chances of occurrence of one variable is expressed in terms of the other variable which is usually sample space.

The sample space for the event is ²⁰C₃ = 1,140

Let the required event be E ( getting all graduates)

n(E) = ⁵C₃ = 10

Therefore, P(getting all graduates) = n(E)/S

= 10/1140

= 1/114