## Kerala Plus One Maths Chapter Wise Previous Questions and Answers Chapter 16 Probability

Question 1.

Once card is drawn at random from a pack of 52 playing cards. Find the probability that, [March.2018]

a. the card drawn is black.

b. the card drawn is a face card.

c. the card drawn ¡s a black face card.

Answer:

Question 2.

a.Match the following :

b. Two dice are thrown at random .Find the probability of …………………

i. getting a doublet

ii. getting sum of the numbers on the dice 8. [March – 2017]

Answer:

b. If two dice are thrown, n(S) = 6^{2} = 36 Doublets are : (1, 1), (2, 2), (3, 3), (4, 4), (5,5) and (6,6)

i. P(doublet) ==

ii. The events whose sum = 8 are ; (2, 6),(3,5), (4,4), (5,3) and (6,2).

p (sum=8)=

Question 3.

In a random experiment, 6 coins are tossed simultaneously. Write the number of sample points in the sample space.

i. 2^{2}

ii. 2^{4 }iii. 2^{6}

iv. 2^{8 } [March – 2016]

Answer:

.

Question 4.

a. The number of outcomes in the sample space of the random experiment of throwing two dice is……..

i.6^{3}

ii. 6

iii.6^{2}

iv. 12

b. Two students Anil and Ashima appeared in an examination. The probability that Anil will qualify the examination is 0.05 and that Ashima will qualify the examination is 0.10. The probability that both will qualify the examination is 0.02. Find the probability that both will not qualify the examination. [March-2015]

Answer:

a. 6^{2 }b. p(A∪B)

Question 5.

a. A coin is tossed repeatedly until a head comes up. Write the sample space.

b. If A and Bare two events in a random experiment, then

P (A∪B) = P (A) + P (B) -…………………..

c. Let P(A) = ,P(B)= ,P(A∩B) =. Find P (not A and not B)

d. A bag contains 9 discs of which 4 are red, 3 are blue, and 2 are yellow. A disc is drawn at random from the bag. Calculate the probability that it will be

i. Red

ii. Not yellow [March-2014]

Answer:

Question 6.

a If A and B are two events in a random experiment, then, P(A) + P(B) – P(A∩B) = ……………..

b. Given P (A) = 0.5, P (B) = 0.6 and P(A∩B) = 0.3. Find P(A∪B ) and P(A)’

c. Two dice are thrown simultaneously. Find the probability of getting a doublet

(same number on both dice) [March-2013]

Answer:

a. P(A∪B)

i.e„ {(1,1), (2,2), (3,3), (4,4), (5,5), (6,6)} 6/36=1/6

Question 7.

i. A coin is tossed repeatedly until a tail comes up. Write the sample for this experiment.

ii. Three coins are tossed once. Find the probability of getting:

a. atleast one head

b. atmost one head

c. exactly one head [February-2013]

Answer:

i.S = {T, HT, HHT, HHHT, HHHHT,….. }

S = {(HHT),(HHHT), (HTH), (THH), (TTT), (TTH), (THT), (HTT)}

a.

b. =

c.

Question 8.

In a class of 60 students, 30 opted for NCC, 32 opted for NSS and 24 opted for both NCC and NSS. If one of these students is selected at random, find:

a. The probability that the student opted for NCC or NSS.

b. The probability that the student opted for exactly one of NCC or NSS. [March-2012]

Answer:

a.

Question 9.

i. If is the probability of an event A, then what is the probability of the even ‘not A’.

ii. If P (A) = and P (B) = , find P (A∪B) if A and B are mutually exclusive events.

iii. A coin is tossed twice. What is the probability that atleast one tail occurs? [March-2011]

Answer:

p(at least one tail)=3/4

Question 10.

Two student A and B, appeared in an examination. The probability that A passes the exam is 0.25 and that B passes is 0.45. Also the probability that both will pass is 0.1. Find the probability that:

i. Both will not pass.

ii. Only one of them will pass. [March-2010]

Answer:

Question 11.

If M and N are two events such that

P (M) = 1/4, P(N) = 14, P (M∩N) = 1/16. Find

a. P(M or N)

b. P (not M and not N) [September-2010]

Answer:

a.P(M∪N) = P(M)+P(N)-P(M∩N)