If 12C5 + 12C6 = XC6, then what is the value of X?
Options
A11
B12
C13
Correct Answer
D18
Correct Answer
Option C is the correct answer.
Detailed Explanation
This is an application of Pascal's Identity, which states that nCr + nCr+1 = n+1Cr+1.In this case, n = 12 and r = 5.So, 12C5 + 12C6 = 12+1C5+1 = 13C6.Comparing this with XC6, we find that X = 13.
