Sawaal
764
Q:

A bag contains 6 white and 4 black balls .2 balls are drawn at random. Find the probability that they are of same colour.

A) 1/2 B) 7/15
C) 8/15 D) 1/9

Answer:   B) 7/15



Explanation:

Let S be the sample space

 

Then n(S) = no of ways of drawing 2 balls out of (6+4) =10C2 10 =10*92*1 =45

 

Let E = event of getting both balls of same colour

 

Then,n(E) = no of ways (2 balls out of six) or (2 balls out of 4)

 

                =6C2+4C2 = 6*52*1+4*32*1= 15+6 = 21

 

Therefore, P(E) = n(E)/n(S) = 21/45 = 7/15

Subject: Probability
Related Questions
Q:

Find the range and mode of the data 17, 18, 28, 19, 16, 18, 17, 29, 18

A) 12 and 18 B) 13 and 18
C) 12 and 17 D) 11 and 17
 
Answer & Explanation Answer: B) 13 and 18

Explanation:
Report Error

View Answer Report Error Discuss

Filed Under: Probability
Exam Prep: Bank Exams

30 2071
Q:

Find the standard deviation of {11, 7, 10,13, 9}

A) 1 B) 2
C) 4 D) 5
 
Answer & Explanation Answer: B) 2

Explanation:
Report Error

View Answer Report Error Discuss

Filed Under: Probability
Exam Prep: Bank Exams

8 1446
Q:

A table tennis player, lost 12 games out of 18 games played. Calculate the games won in terms of decimal.

A) 0.667 B) 0.067
C) 0.50 D) 0.333
 
Answer & Explanation Answer: D) 0.333

Explanation:
Report Error

View Answer Report Error Discuss

Filed Under: Probability
Exam Prep: Bank Exams

7 1284
Q:

A sequence a, ax, ax2, ......, axn, has odd number of terms. Then the median is

 

A) axn2+1 B) axn2-1
C) axn-1 D) axn2
 
Answer & Explanation Answer: D) axn2

Explanation:
Report Error

View Answer Report Error Discuss

Filed Under: Probability
Exam Prep: Bank Exams

6 17588
Q:

The mean of a distribution is 15 and the standard deviation is 5. What is the value of the coefficient variation?

A) 16.66% B) 66.66%
C) 33.33% D) 100%
 
Answer & Explanation Answer: C) 33.33%

Explanation:
Report Error

View Answer Report Error Discuss

Filed Under: Probability
Exam Prep: Bank Exams

9 1232
Q:

If the standard deviation of a population is 3, what would be the population variance?

 

A) 9 B) 6
C) 8 D) 15
 
Answer & Explanation Answer: A) 9

Explanation:
Report Error

View Answer Report Error Discuss

Filed Under: Probability
Exam Prep: Bank Exams

7 14709
Q:

The variance of a set of data is 169. Then the standard deviation of the data is

 

A) +-13 B) 13
C) 69 D) 84.5
 
Answer & Explanation Answer: B) 13

Explanation:
Report Error

View Answer Report Error Discuss

Filed Under: Probability
Exam Prep: Bank Exams

6 12653
Q:

If the standard deviation of a population is 10, what would be the population variance?

A) 100 B) 30
C) 5 D) 20
 
Answer & Explanation Answer: A) 100

Explanation:
Report Error

View Answer Report Error Discuss

Filed Under: Probability
Exam Prep: Bank Exams

10 1312