What is the probability that a number selected at random

Question:

What is the probability that a number selected at random from the number 1, 2, 2, 3, 3, 3, 4, 4, 4, 4 will be their average?

Solution:

GIVEN: A number is selected from the numbers 1,2,2,3,3,3,4,4,4,4

TO FIND: Probability that the selected number is the average of the numbers

Total numbers are 10

Average of numbers is

$=\frac{1+2+2+3+3+3+4+4+4+4}{10}$

$=\frac{30}{10}$

$=3$

Total numbers of numbers which are average of these numbers are 3

We know that PROBABILITY =

Hence Probability that the selected number is the average of the numbers =