NCERT Class 12-Mathematics: Chapter –13 Probability Part 7
Get top class preparation for KVPY/Stream-SA Mathematics right from your home: fully solved questions with step-by-step explanation- practice your way to success.
Question 8:
Three events A, B and C have probabilities respectively. Given that , find the values of and .
Answer:
Here,
And
Question 9:
Let and be two independent events such that and . Describe in words of the events whose probabilities are:
(i)
(ii)
(iii)
(iv)
Answer:
(i) and occur
(ii) does not occur, but occurs
(iii) Either or , or both and occurs
(iv) Either or occurs, but not both
Question 10:
A discrete random variable X has the probability distribution given as below:
(i) Find the value of
(ii) Determine the mean of the distribution.
Answer:
We have
(i) we know that,
(ii) Mean of the distribution
Question 11:
Prove that
(i)
(ii)
Answer:
(i)
Hence proved.
(ii)
Hence proved.
Question 12:
If X is the number of tails in three tosses of a coin, determine the standard deviation of X.
Answer:
Question 13:
In a dice game, a player pays a stake of Re1 for each throw of a die. She receives Rs 5 if the die shows a 3, Rs 2 if the die shows a 1 or 6, and nothing otherwise. What is the player’s expected profit per throw over a long series of throws?
Answer: