Gamma Question Bank for Engineering Mathematics>Chapter 21 - Probability>EXERCISE 14.3>Q 23

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$n$ letters are written to $n$ different persons and addresses on the $n$ envelopes are also written. If the letters are placed in the envelopes at random, the probability that at least one letter is not placed in the right envelope, is

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Important Questions on Probability

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Gamma Question Bank for Engineering Mathematics>Chapter 21 - Probability>EXERCISE 14.3>Q 24

6

girls and

5

boys sit together randomly in a row, the probability that no two boys sit together, is

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Gamma Question Bank for Engineering Mathematics>Chapter 21 - Probability>EXERCISE 14.3>Q 25

The probability of guessing correctly at least

8

out of

10

answers on a true-false examination, is

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Gamma Question Bank for Engineering Mathematics>Chapter 21 - Probability>EXERCISE 14.3>Q 26

Three of the six vertices of a regular hexagon are chosen at random. The probability that the triangle with three vertices is equilateral, equals

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Gamma Question Bank for Engineering Mathematics>Chapter 21 - Probability>EXERCISE 14.3>Q 27

One mapping is selected at random from all the mappings of the set

A = \{1, 2, 3, \dots, n\}

into itself. The probability that the mapping selected is one to one mapping is given by

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Gamma Question Bank for Engineering Mathematics>Chapter 21 - Probability>EXERCISE 14.3>Q 28

A natural number

x

is chosen at random from the first

100

natural numbers. The probability that

x + \frac{100}{x} > 50

is

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Gamma Question Bank for Engineering Mathematics>Chapter 21 - Probability>EXERCISE 14.3>Q 29

The probability that at least one of the events

A

and

B

occurs is

0.6.

If

A

and

B

occur simultaneously with probability

0.2,

then

P (\bar{A}) + P (\bar{B})

is: (where

\bar{A}

and

\bar{B}

are complements of

A

and

B

respectively)

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Gamma Question Bank for Engineering Mathematics>Chapter 21 - Probability>EXERCISE 14.4>Q 30

The probability that a man aged

x

years will die in a year is

p

. The probability that out of

n

men

M_{1}, M_{2}, \dots

M_{n}

, each aged

x

,

M_{1}

will die and be the first to die, is

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Gamma Question Bank for Engineering Mathematics>Chapter 21 - Probability>EXERCISE 14.4>Q 31

Three athletes

A, B

and

C

participate in a race. Both

A

and

B

have the same probability of winning the race and each is twice as likely to win as

C

. The probability that

B

or

C

wins the race is