Question Detail

STA 112 PERMUTATIONS AND COMBINATIONS Objective Question
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Question

What is the value of r, if 12C5 = 12Cr?
Options
A 5 or 7
Correct Answer
B 6
C 8
D 10
Correct Answer

Option A is the correct answer.

Detailed Explanation

The property of combinations states that if nCx = nCy, then either x = y or x + y = n.In this case, n = 12, x = 5, and y = r.So, either r = 5 or 5 + r = 12.If 5 + r = 12, then r = 12 - 5 = 7.Thus, r can be 5 or 7.

Hint

Apply the property: if nCx = nCy, then x = y or x + y = n.

Question Info

Course: STA 112
Topic: PERMUTATIONS AND COMBINATIONS
Type: Objective
Difficulty: Not specified
Question 108 of 112
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