CBSE

CBSE Study Material

An urn contains 5 white and 8 black balls. Two successive drawings of 3 balls at a time are made such that the balls drawn in the first draw are not replaced before the second draw. Find the probability that the first draw gives 3 white balls and the second draw gives 3 black balls.

Let, success in the first draw be getting 3 white balls. Now, the Probability of success in the first trial is $P_{1}(\text { success })=\frac{5_{c_{3}}}{13_{c_{3}}}=\frac{10}{286}=\frac{5}{143}$...

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In a hostel, 60 \% of the students read Hindi newspaper, 40 \% read English newspaper and 20 \% read both Hindi and English newspapers. A student is selected at random. If he reads English newspaper, what is the probability that he reads Hindi newspaper?

Let $\mathrm{P}(\mathrm{A})$ be the probability of students reading Hindi newspaper. $\therefore P(A)=0.60$ Let $\mathrm{P}(\mathrm{B})$ be the probability of them reading English newspaper....

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In a hostel, 60 \% of the students read Hindi newspaper, 40 \% read English newspaper and 20 \% read both Hindi and English newspapers. A student is selected at random.
(i) Find the probability that he reads neither Hindi nor English news paper.
(ii) If he reads Hindi newspaper, what is the probability that he reads English newspaper?

Let $\mathrm{P}(\mathrm{A})$ be the probability of students reading Hindi newspaper. $\therefore P(A)=0.60$ Let $\mathrm{P}(\mathrm{B})$ be the probability of them reading English newspaper....

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The probability that a certain person will buy a shirt is 0.2, the probability that he will buy a coat is 0.3 and the probability that he will buy a shirt given that he buys a coat is 0.4 . Find the probability that he will buy both a shirt and a coat.

Let $\mathrm{P}(\mathrm{A})$ be the probability of a certain person buying a shirt. $\therefore \mathrm{P}(\mathrm{A})=0.2$ Let $P(B)$ be the probability of him buying a coat. $\therefore P(B)=0.3$...

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The probability that a student selected at random from a class will pass in Hindi is \frac{4}{5} and the probability that he passes in Hindi and English is \frac{1}{2}. What is the probability that he will pass in English if it is known that he has passed in Hindi?

One student is selected at random. Let $\mathrm{P}(\mathrm{A})$ be the probability of students passing in English. Let $\mathrm{P}(\mathrm{B})$ be the probability of students passing in Hindi....

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In a class, 40 \% students study mathematics; 25 \% study biology and 15 \% study both mathematics and biology. One student is selected at random. Find the probability that
(i) he studies mathematics if it is known that he studies biology
(ii) he studies biology if it is known that he studies mathematics.

Let $\mathrm{P}(\mathrm{A})$ be the probability of students studying mathematics. $\therefore P(A)=0.40$ Let $\mathrm{P}(\mathrm{B})$ be the probability of students studying biology. $\therefore...

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