Question Detail

STA 112 PERMUTATIONS AND COMBINATIONS Objective Question
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Question

If nCr + nCr+1 = n+1Cx, then x = ?
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 Pascal's rule or addition formula) in combinations.Pascal's Identity states that nCr + nCr+1 = n+1Cr+1.Comparing this with the given equation nCr + nCr+1 = n+1Cx, we can conclude that x must be equal to r+1.

Hint

Recall Pascal's Identity for combinations.

Question Info

Course: STA 112
Topic: PERMUTATIONS AND COMBINATIONS
Type: Objective
Difficulty: Not specified
Question 83 of 112
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