Probability Worksheet Solution12





In this page probability worksheet solution12 we are going to see solution of some practice questions of the probability worksheet.

Question 10

A card is drawn at random from a well-shuffled deck of 52 cards. Find the probability that it will be a spade or a king.

Solution:

Sample space = Total number of cards = 52

 n (S) = 52

Number of spade card = 13

Number of king card = 4

Let A be the event of getting a spade card

n (A) = 13

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

        = 13/52

Let B be the event getting a king card

n (B) = 4

 P (B) = n (B)/n (S)

         = 4/52

Number of spade king card = 1

n (A ∩ B) = 1

P (A ∩ B) = n (A ∩ B)/n (S)

             = 1/52

P (A U B) =  P (A) + P (B) - P (A ∩ B)

              = (13/52) + (4/52) - (1/52)

              = (13 + 4 - 1)/52

              = 16/52

   P (A U B) = 9/13


Question 11

A box contains 10 white,6 red and 10 black balls. A ball is drawn at random. Find the probability that the ball drawn is white or red.

Solution:

Sample space = 10 + 6 + 10

            n (S) = 26 balls

Let A be the event of getting a white ball

 n (A) = 10

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

        = 10/26

Let B be the event of getting a red ball

 n (B) = 6

 P (B) = n (B)/n (S)

         = 6/26

Since both the events are mutually exclusive

 So , p (A ∩ B) = 0

P (A U B) = P (A) + P (B) - P (A ∩ B)

              = (10/26) + (6/26) - 0

              = (10 + 6)/26

P (A U B) = 16/26

probability worksheet solution12 probability worksheet solution12