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29. There are four men and six women on the city council. If one council member is selected for a committee at random, how likely is it that it is a woman?
29. There are four men and six women on the city council. If one council member is selected for a committee at random, how likely is it that it is a woman?
29. Number of women in the city council n (A) = 6
As there are four men and six women the total number of person in the sample space is 4 + 6 = 10.
So, n (S) = 10
P (A) =
28. A fair coin with 1 marked on one face and 6 on the other and a fair die are bothtossed. find the probability that the sum of numbers that turn up is (i) 3 (ii) 12
28. A fair coin with 1 marked on one face and 6 on the other and a fair die are bothtossed. find the probability that the sum of numbers that turn up is (i) 3 (ii) 12
28. The sample space of the experiment is
S = { (1, 1), (1, 2), (1, 3), (1, 4), (1, 5), (1, 6), (6, 1), (6, 2), (6, 3), (6, 4), (6, 5) (6, 6)}
So, n (S) = 12.
(i) Let E be event such that sum of numbers that turn up is 3. Then,
E = { (1, 2)}
So, n (E) = 1
P (E) = .
(ii) Let
27. A card is selected from a pack of 52 cards.
(a) How many points are there in the sample space?
(b) Calculate the probability that the card is an ace of spades.
(c) Calculate the probability that the card is (i) an ace (ii) black card.
27. A card is selected from a pack of 52 cards.
(a) How many points are there in the sample space?
(b) Calculate the probability that the card is an ace of spades.
(c) Calculate the probability that the card is (i) an ace (ii) black card.
27. (a) Since there are 52 cards in the sample space,
n (S) = 52.
So, there are 52 sample points.
(b) In a deck of 52 cards there are 4 ace cards of which only one is of spades.
Hence, if A be an event of getting an ace of spades.
n (A) = 1
So, P (A) = .
(c) (i) Let B be an event of dra
26. A die is thrown, find the probability of following events:
(i) A prime number will appear,
(ii) A number greater than or equal to 3 will appear,
(iii) A number less than or equal to one will appear,
(iv) A number more than 6 will appear,
(v) A number less than 6 will appear.
26. A die is thrown, find the probability of following events:
(i) A prime number will appear,
(ii) A number greater than or equal to 3 will appear,
(iii) A number less than or equal to one will appear,
(iv) A number more than 6 will appear,
(v) A number less than 6 will appear.
26. The sample space of throwing s dice is
S = {1, 2, 3, 4, 5, 6}, n (S) = 6.
(i) Let A be event such that a prime number will appear. Then,
A = {2, 3, 5}
? n (A) = 3
Here; P (A) =
(ii) Let B be event such that a number greater than or equal to 3 will appear. Then
B = {3, 4, 5, 6}
So
25. A coin is tossed twice, what is the probability that atleast one tail occurs?
25. A coin is tossed twice, what is the probability that atleast one tail occurs?
25. When a coin is tossed twice we have the sample space
S = {TT, TH, HT, HH}
So, n (S) = 4
Let A be the event of getting at least one tail.
Then, A = {TH, HT, TT}
So, n (A) = 3
Therefore, P (A)= Numver of outcome favorable to A/Total possible outcomes = .
24. Which of the following can not be valid assignment of probabilities for outcomes
of sample Space S = {ω1, ω2, ω3, ω4, ω5, ω6, ω7,}
Assignment ω 1 ω 2 ω 3 ω 4 ω 5 ω 6 ω 7
(a) 0.1 0.01 0.05 0.03 0.01 0.2 0.6
(b)
(c) 0.1 0.2 0.3 0.4 0.5 0.6 0.7
(d) – 0.1 0.2 0.3 0.4 – 0.2 0.1 0.3
(e)
24. Which of the following can not be valid assignment of probabilities for outcomes
of sample Space S = {ω1, ω2, ω3, ω4, ω5, ω6, ω7,}
Assignment ω 1 ω 2 ω 3 ω 4 ω 5 ω 6 ω 7
(a) 0.1 0.01 0.05 0.03 0.01 0.2 0.6
(b)
(c) 0.1 0.2 0.3 0.4 0.5 0.6 0.7
(d) – 0.1 0.2 0.3 0.4 – 0.2 0.1 0.3
(e)
24. (a) P (S) = P (W1) + P (W2) +P (W3) + P (W4) +P (W5) +P (W6) +P (W7)
P (S) = 0.1 + 0.01 + 0.05 + 0.03 + 0.01 + 0.2 + 0.6
P (S) = 1
As the probability of sample space is ‘one’ the given assignment of probabilities is valid.
(b) P (S) = P (W1) + P (W2) +P (W3) + P (W4) +P (W5) +P (W6) +P (W7)
P (S) =
23. Refer to question 6 above, state true or false: (give reason for your answer)
(i) A and B are mutually exclusive
(ii) A and B are mutually exclusive and exhaustive
(iii) A = B′
(iv) A and C are mutually exclusive
(v) A and B′ are mutually exclusive.
(vi) A′, B′, C are mutually exclusive and exhaustive.
23. Refer to question 6 above, state true or false: (give reason for your answer)
(i) A and B are mutually exclusive
(ii) A and B are mutually exclusive and exhaustive
(iii) A = B′
(iv) A and C are mutually exclusive
(v) A and B′ are mutually exclusive.
(vi) A′, B′, C are mutually exclusive and exhaustive.
23. (i) A ∩B = { (2, 1), (2, 2), (2, 3), (2, 4), (2, 5), (2, 6),
(4, 1), (4, 2), (4, 3), (4, 4), (4, 5), (4, 6),
(6, 1), (6, 2), (6, 3), (6, 4), (6, 5), (6, 6)}∩ { (1, 1), (1, 2), (1, 3), (1, 4), (1, 5), (1, 6),
(3, 1), (3, 2), (3, 3), (3, 4), (3, 5), (3, 6),
22. Two dice are thrown. The events A, B and C are as follows:
A: getting an even number on the first die.
B: getting an odd number on the first die.
C: getting the sum of the numbers on the dice ≤ 5.
Describe the events
(i) A′ (ii) Not B (iii) A or B
(iv) A and B (v) A but not C
(vi) B or C (vii) B and C (viii) A ∩ B′ ∩ C′
22. Two dice are thrown. The events A, B and C are as follows:
A: getting an even number on the first die.
B: getting an odd number on the first die.
C: getting the sum of the numbers on the dice ≤ 5.
Describe the events
(i) A′ (ii) Not B (iii) A or B
(iv) A and B (v) A but not C
(vi) B or C (vii) B and C (viii) A ∩ B′ ∩ C′
22. The sample space of the experiment is
S = { (1, 1), (1, 2), (1, 3), (1, 4), (1, 5), (1, 6),
(2, 1), (2, 2), (2, 3), (2, 4), (2, 5), (2, 6),
(3, 1), (3, 2), (3, 3), (3, 4), (3, 5), (3, 6),
(4, 1), (4, 2), (4, 3), (4, 4), (4, 5), (4, 6),
(5, 1), (5, 2), (5, 3), (5, 4
21. Three coins are tossed. Describe
(i) Two events which are mutually exclusive.
(ii) Three events which are mutually exclusive and exhaustive.
(iii) Two events, which are not mutually exclusive.
(iv) Two events which are mutually exclusive but not exhaustive.
(v) Three events which are mutually exclusive but not exhaustive.
21. Three coins are tossed. Describe
(i) Two events which are mutually exclusive.
(ii) Three events which are mutually exclusive and exhaustive.
(iii) Two events, which are not mutually exclusive.
(iv) Two events which are mutually exclusive but not exhaustive.
(v) Three events which are mutually exclusive but not exhaustive.
21. The sample space of the experiment is
S = {HHH, HHT, HTH, HTT, THH, THT, TTH, TTT}
(i) Let A and B be two events such that
A: only head occurs
A = {HHH}
B: only tail occurs
B = {TTT}
And A ∩B = {HHH}∩ {TTT} =∅
(ii) Let A, B and C be two events such that
A: at most one head (i.e., the event in which we
20. Three coins are tossed once. Let A denote the event ‘three heads show”, B denote the event “two heads and one tail show”, C denote the event” three tails
show and D denote the event ‘a head shows on the first coin”. Which events are
(i) Mutually exclusive ? (ii) Simple? (iii) Compound?
20. Three coins are tossed once. Let A denote the event ‘three heads show”, B denote the event “two heads and one tail show”, C denote the event” three tails
show and D denote the event ‘a head shows on the first coin”. Which events are
(i) Mutually exclusive ? (ii) Simple? (iii) Compound?
20. The sample space of the experiment is
S = {HHH, HHT, HTH, THH, HTT, THT, TTH, TTT}
Now, A = {HHH}
B = {HHT, HTH, THH}
C = {TTT}
D = {HHH, HHT, HTH, HTT}
(i) A∩ B = {HHH}∩ {HHT, HTH, THH} =∅
A ∩ C = {HHH}∩ {TTT} =∅
A∩ D = {HHH}∩ {HHH, HTH, HTT} = {HHH}
B ∩ C = {HHT, HTH, THH}∩ {TTT} =∅
B∩ D = {HHT, HTH, T