JEE MATHEMATICS MCQ: PROBABILITY

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A box contain

N

coins,

m

of which are fair and rest are biased. The probability of getting a head when a fair coin is tossed is

1 / 2

, while it is

2 / 3

when a biased coin is tossed. A coin is drawn from the box at random and is tossed twice. The first time it shows head and the second time it shows tail. The probability that the coin drawn is fair is

View answer and explanation

Correct option: C

\frac{9 m}{8 N+m}

Option C (

\frac{{9 m}}{{8 N+m}}

) is correct because it represents the probability that the coin drawn is fair, given the observed sequence of head and tail, using Bayes' theorem.

More Questions from PROBABILITY

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Consider the probability distribution

\begin{array}{cccccc}X: & 1 & 2 & 3 & 4 & 5 \\ P(X): & k^2 & 2 k & k & 2 k & 5 k^2\end{array}

The value of

P(X>2)

is A bag contains

\left( {2\;n + 1} \right)

coins. It is known that

n

of these coins have a head on both sides, whereas the remaining

n + 1

coins are fair. A coin is picked up at random from the bag and tossed. If the probability that the toss results in a head is 31/42, then

n

is equal to The probability that a bulb produced by a factory will fuse after 150 days of use is 0.05 . What is the probability that out of 5 such bulbs none will fuse after 150 days of use If

A

and

B

are two independent events such that

P\left( {A \cap B'} \right) = \frac{3}{{25}}

and

P\left( {A' \cap B} \right) = \frac{8}{{25}}

, then

P\left( A \right)

is equal to In a game two players

A

and

B

take turns in throwing a pair of fair dice starting with player

A

and total of scores on the two dice, in each throw is noted. A wins the game if he throws a total of 6 before

B

throws a total of 7 and

B

wins the game if he throws a total of 7 before A throws a total of six. The game stops as soon as either of the player wins. The probability of

A

winning the game is A box contains 5 brown and 4 white socks. A man takes out two socks. The probability that they are of the same colour is