How many 3 members committe can be selected from a class of 20 students?
To find out the number of 3-member committees that can be selected from a class of 20 students, we can use the concept of combinations.
The formula for combinations is given by:
nCr = n! / (r!(n-r)!)
Where:
n = total number of items
r = number of items to be selected
In this case, n = 20 (the total number of students in the class) and r = 3 (the number of students to be selected for the committee).
Using the formula, we can calculate the number of 3-member committees:
20C3 = 20! / (3!(20-3)!)
= 20! / (3!17!)
Calculating the factorial expressions, we get:
20C3 = (20 * 19 * 18 * 17!) / (3 * 2 * 1 * 17!)
= (20 * 19 * 18) / (3 * 2 * 1)
= 1140
Therefore, there are 1140 different 3-member committees that can be selected from a class of 20 students.