Q8 of 158 Page 33

The numbers 1, 2, 3 and 4 are written separately on four slips of paper. The slips are then put in a box and mixed thoroughly. A person draws two slips from the box, one after the other, without replacement. Describe the following events:

A = The number on the first slip is larger than the one on the second slip.


B = The number on the second slip is greater than 2


C = The sum of the numbers on the two slips is 6 or 7


D = The number on the second slips is twice that on the first slip.


Which pair (s) of events is (are) mutually exclusive?

Given: There are 4 slips in the box and mixed thoroughly.


To Find: Describe the given events .


Explanation: Here, Four slips of paper 1, 2, 3, and 4 are put in a box.


If Two slips are drawn from it one after the other without replacement. Then


The sample space for the experiment is:


S = {(1, 2)(1, 3), (1, 4)(2, 1)(2, 3)(2, 4)(3, 1)(3, 2)(3, 4)(4, 1)(4, 2)(4, 3)}


(i) A = number on the first slip is larger than the one on the second slip,


So, The sample space for A is:


{(2, 1)(3, 1)(3, 2)(4, 1)(4, 2)(4, 3)}


(ii) B = number on the second slip is greater than 2


So, The sample space for B is


{(1, 3)(2, 3)(1, 4)(2, 4)(3, 4)(4, 3)}


(iii) C = sum of the numbers on the two slips in 6 or 7


The sample space for C is


{(2, 4)(3, 4)(4, 2)(4, 3)}


(iv) D = number on the second slip is two times the number on the first slip


The sample space if:


{(1, 2)(2, 4)}


Now,


We can see, AՌD = Փ


Therefore, A and D are mutually exclusive events


Hence, A and D are mutually exclusive events.


More from this chapter

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6

A die is thrown twice. Each time the number appearing on it is recorded. Describe the following events:

(i) A = Both numbers are odd.


(ii) B = Both numbers are even


(iii) C = sum of the numbers is less than 6.


Also, find A B, A B, A C, A C. Which pairs of events are mutually exclusive.

7

Two dice are thrown. The events A, B, C, D, E and F are describes as follows.

A = Getting an even number on the first die.


B. Getting an odd number on the first die.


C = Getting at most 5 as sum of the numbers on the two dice.


D = Getting the sum of the numbers on the dice greater than 5 but less than 10.


E = Getting at least 10 as the sum of the numbers on the dice.


F = Getting an odd number on one of the dice.


(i) Describe the following events: A and B, B or C, B and C, A and E, A or F, A and F


(ii) State true or false:


(a) A and B are mutually exclusive.


(b) A and B are mutually exclusive and exhaustive events


(c) A and C are mutually exclusive events


(d) C and D are mutually exclusive and exhaustive events


(e) C, d and E are mutually exclusive and exhaustive events


(f) A’ and B’ are mutually exclusive events


(g) A, B, F are mutually exclusive and exhaustive events

9

A card is picked up from a deck of 52 playing cards.

(i) What is the sample space of the experiment?


(ii) What is the event that the chosen card is a black faced card?

1

Which of the following cannot be valid assignment of probability for elementary events or outcomes of sample space S = {w1, w2, w3, w4, w5, w6, w7}:





















































Elementary events:



w1



w2



w3



w4



w5



w6



w7



(i)



0.1



0.01



0.05



0.03



0.01



0.2



0.6



(ii)

















(iii)



0.7



0.6



0.5



0.4



0.3



0.2



0.1



(iv)