Question Detail

STA 112 PERMUTATIONS AND COMBINATIONS Objective Question

Question

If nCr + nCr+1 = n+1Cx, then the value of x is:
Options
A r
B r-1
C n
D r + 1
Correct Answer
Correct Answer

Option D is the correct answer.

Detailed Explanation

This is a direct application of Pascal's Identity (also known as the combination identity), which states that nCr + nCr+1 = n+1Cr+1.Comparing this with the given equation nCr + nCr+1 = n+1Cx, we can conclude that x = r+1.

Hint

This is a fundamental identity in combinations, often called Pascal's Identity.

Question Info