richachampion wrote:Set A consists of K distinct numbers. If N numbers are selected from the set one-by-one, where N≤K, what is the probability that numbers will be selected in ascending order?
(1) Set A consists of 12 even consecutive integers."‹"‹
(2) N=5
Statement 1:
Case 1: n=2
Here, 2 distinct numbers are selected.
The number of orderings in which 2 distinct numbers can be selected = 2!.
Since only one of these 2! ways will be in ascending order, P(ascending order) = 1/2!.
Case 2: n=5
Here, 5 distinct numbers are selected.
The number of orderings in which 5 distinct numbers can be selected = 5!.
Since only one of these 5! ways will be in ascending order, P(ascending order) = 1/5!.
Since the probability can be different values, INSUFFICIENT.
Statement 2:
As illustrated by Case 2, if n=5, then P(ascending order) = 1/5!.
SUFFICIENT.
The correct answer is
B.
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