One mapping is selected at random from all mappings of the set `S={1,2,3, n}` into itself. If the probability that the mapping is one-one is 3/32, the
One mapping is selected at random from all mappings of the set `S={1,2,3, n}`
into itself. If the probability that the mapping is one-one is 3/32,
then the value of `n`
is
`2`
b. `3`
c. `4`
d. none of these
A. 2
B. 3
C. 4
D. none of these
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Correct Answer - C
The total number of mapping is `n^(n)`. The number of one-one mapping is n!. Hence, the probability is
`(n!)/(n^(n))=(3)/(32) = (4!)/(4^(4))`
Comparing, we get n = 4.
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