Question Detail
Question
What is the value of x, if 12C5 + 12C6 = XC6?
Correct Answer
Option C is the correct answer.
Detailed Explanation
This question uses Pascal's Identity for combinations, which states: nCr + nCr+1 = n+1C(r+1).Here, n = 12 and r = 5.So, 12C5 + 12C6 = (12+1)C(5+1) = 13C6.Comparing this to XC6, we find that X = 13.
Hint
Recall Pascal's Identity for combinations: nCr + nCr+1 = n+1Cr+1.