Q. Three individuals have to be selected from a group of 6 people. How many different combinations are possible?
(A) 120
(B) 60
(C) 20
(D) 10
Question from Odisha OCS Paper 2 2024
Correct Answer: (C) 20
Explanation:
To solve this problem, we need to calculate the number of combinations of selecting 3 individuals from a group of 6 people. The formula for combinations is:
nCr = n! / [r!(n – r)!]
Where:
– n is the total number of items (6 in this case),
– r is the number of items to choose (3 in this case),
– ! denotes factorial (e.g., 3! = 3 × 2 × 1 = 6).
Substitute the values into the formula:
6C3 = 6! / [3!(6 – 3)!]
Simplify step by step:
1. 6! = 6 × 5 × 4 × 3 × 2 × 1 = 720
2. 3! = 3 × 2 × 1 = 6
3. (6 – 3)! = 3! = 6
Now substitute these values into the formula:
6C3 = 720 / (6 × 6) = 720 / 36 = 20
Thus, the number of combinations is 20.
Correct Answer: (C) 20