Probability Worksheet Solution4





In this page probability worksheet solution4 we are going to see solution of some practice questions of the probability worksheet.

Question 10

For a sightseeing trip a tourist selects a country randomly from Argentina, Bangladesh, China, Angola, Russia and Algeria. What is the probability that the name of selected country will begin with A?

Solution:

Sample space ={ Argentina, Bangladesh, China, Angola, Russia, Algeria}

                  n(S) = 6

Let A be the event of getting the name begin with “A”

A = { Argentina, Angola, Algeria}

n(A) = 3

Probability of getting the name begin with A,P(A) = n(A)/n(S)

                                                                      = 3/6

                                                                      = 1/2                 


Question 11

A box contains 4 Green, 5 Blue and3 red balls. A ball is drawn at random. Find the probability that the selected ball is

(i) Red in color  

(ii) not green in color

Solution:

There are 4 green balls,5 blue balls and 3 red balls in the box

Total number of balls in the box = 4 + 5 + 3

                                              = 12

Sample space n(S) = 12

(i)Let A be the event of getting a ball in red color

n(A) = 3

Probability of getting red balls, P(A) = n(A)/n(S)

                                                   = 3/12

                                                   = 1/4

(ii)Let B be the event of getting a ball not a green in color

Since it is not green it may be any color wither blue or red

n(B) = 8

Probability of getting red balls, P(B) = n(B)/n(S)

                                                    = 8/12

                                                    = 2/3

(i) Probability of getting red balls, P(A) = 1/4

(ii) Probability of getting red balls, P(B) = 1/4


Question 12

20 cards are numbered from 1 to 20. One card is drawn at random. What is the probability that the number on the card is

(i) a multiple of 4

(ii) not a multiple of 6

Solution:

20 cards are numbered from 1 to 20

Sample space S = {1,2,3,14,5,………………20}

                    n(S) =20

(i) Let A be the event of getting a card which is multiple of 4

A= {4,8,12,16,20}

n(A) = 5

Probability of getting a card which is multiple of 4

P(A) = n(A)/n(S)

         = 5/20

         = 1/4

(ii) To find the probability of getting a card which is not a multiple of 6.First let us find the probability of getting a multiple of 6. Then we have to subtract this probability from 1.

Let B be the event of getting a card which is a multiple of 6

B= {6,12,18}

n(B) = 3

Probability of getting a card which is multiple of 6

P(B) = n(B)/n(S)

         = 3/20                            

(i) Probability of getting a card which is multiple of 4,P(A) = 1/4

(ii) Probability of getting a card which is multiple of 6,P(B) = 3/20

probability worksheet solution4 probability worksheet solution4