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Kris and David work with n other workers. Two of the workers are to be
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26 Dec 2023, 04:43
26 Dec 2023, 04:43
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Kris and David work with n other workers. Two of the workers are to be chosen to work on a new project. What is the expression that gives the probability that both Kris and David will be chosen?
Indicate all possible expressions.
A. \(\dfrac{1}{n^2}\)
B. \(\dfrac{2}{(n+1)(n+2)}\)
C. \(\dfrac{1}{n(n+1)}\)
D. \(\dfrac{2}{n(n+3)+2}\)
E. \(\dfrac{1}{n^2+n}\)
Indicate all possible expressions.
A. \(\dfrac{1}{n^2}\)
B. \(\dfrac{2}{(n+1)(n+2)}\)
C. \(\dfrac{1}{n(n+1)}\)
D. \(\dfrac{2}{n(n+3)+2}\)
E. \(\dfrac{1}{n^2+n}\)
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Free Materials for the GRE General Exam - Where to get it!!
GRE Geometry Formulas
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Kris and David work with n other workers. Two of the workers are to be
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09 Jan 2024, 20:11
09 Jan 2024, 20:11
1
Kris and David work with n other workers. Two of the workers are to be chosen to work on a new project. What is the expression that gives the probability that both Kris and David will be chosen?
The total number of workers, including Kris and David, is \(2+n\).
The probability that either Kris OR David gets chosen the first pick is \(\frac{2}{2+n}\). Now we're left with \(1+n\) total workers, and only one of Kris or David left in the pool.
The probability that the remaining of Kris or David gets chosen the second pick is \(\frac{1}{1+n}\).
Since we're picking without replacement, the probability that both happens is \(\frac{2}{2+n}*\frac{1}{1+n} = \frac{2}{(n+1)(n+2)} = \frac{2}{n(n+3)+2}\)
The total number of workers, including Kris and David, is \(2+n\).
The probability that either Kris OR David gets chosen the first pick is \(\frac{2}{2+n}\). Now we're left with \(1+n\) total workers, and only one of Kris or David left in the pool.
The probability that the remaining of Kris or David gets chosen the second pick is \(\frac{1}{1+n}\).
Since we're picking without replacement, the probability that both happens is \(\frac{2}{2+n}*\frac{1}{1+n} = \frac{2}{(n+1)(n+2)} = \frac{2}{n(n+3)+2}\)
gmatclubot
Kris and David work with n other workers. Two of the workers are to be [#permalink]
09 Jan 2024, 20:11
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