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There are x people at a dance, where x is an integer
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07 Apr 2019, 06:16
07 Apr 2019, 06:16
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There are \(X\) people at a dance, where \(X\) is an integer greater than 1. The number of different pairs of people who can be partnered up for the waltz is \(Z\). Which of the following could be the value of \(Z\)?
A. 2
B. 6
C. 9
D. 14
E. 20
A. 2
B. 6
C. 9
D. 14
E. 20
Re: There are x people at a dance, where x is an integer
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07 Apr 2019, 23:33
07 Apr 2019, 23:33
solution please?
Re: There are x people at a dance, where x is an integer
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08 Apr 2019, 03:20
08 Apr 2019, 03:20
Expert Reply
\(z = \frac{x!}{[2!(x - 2)!]}\)
Let's try a few possibilities for \(X\). We know \(x > 1\) .
If x = 2, then there will only be 1 pair of dancers, but 1 isn't an answer choice.
If x = 3, then z = 3, but that isn't an answer choice.
If x = 4, then z = 6. The correct answer is (B).
Let's try a few possibilities for \(X\). We know \(x > 1\) .
If x = 2, then there will only be 1 pair of dancers, but 1 isn't an answer choice.
If x = 3, then z = 3, but that isn't an answer choice.
If x = 4, then z = 6. The correct answer is (B).
