Question

How many ways can we choose three items at random without replacement from five items (A, B, C, D, E) if the order of the selected items is not important?
a) 60
b) 120
c) 10
d) 24

Answer 1

Answer:

10

Step-by-step explanation:

This is a combination problem.

Given the set of items S = (A, B, C, D, E)

Total number of items in the set = 5

Amount to select is 3 items

This can be done in 5C3 number of ways

5C3 = 5!/(5-3)!3!

5C3 = 5!/2!3!

5C3 = 5*4*3!/2*3!

5C3 = 5*4/2

5C3 = 20/2

5C3 = 10

Hence this can be done in 10 ways if orders are not important