CBSE - Probability

1 Probability 

 A bag contains 10 red balls and some white balls. If the probability of drawing a white ball is double that of a red ball, then number of white balls in the bag will be 
 
1) 10
2) 15
3) 20 
4) 25 

2 Probability 

 Probability that a non leap year should have 53 Mondays, will be  
 
1) 2 / 7
2) 3 / 7
3) 1 / 7
4) 5 / 7

3 Probability 

A bag contains 2 red, 3 green and 2 blue  balls. Two balls are drawn at random. What is the probability that none  of the balls drawn is blue? 
 
1)  10 / 21
2)  11 / 21
3)  2 / 7
4) 5 / 7 

4 Probability 

A letter is chosen at random from the word “probability”. The probability that it is a vowel is  
 
1) 1 / 11
2) 2 / 11
3) 3 / 11
4) 4 / 11

5 Probability 

In a class, there are 15 boys and 10 girls. Three students are selected at random. The probability that 1 girl and 2 boys are selected, is: 
 
1) 21 / 46
2) 25 / 117
3) 1 / 50
4) 3 / 25 

6 Probability 

The probability of guessing the correct answer to a certain question is p/12. If the probability of not guessing the correct answer to the same question is 3/4, the value of p is  
 
1) 3
2) 4
3) 2
4) 1

7 Probability 

A die is thrown twice. The probability that 5 will not come up either of the time is :

(1) 35/36  
(2) 25/36 
(3) 1 / 36 
(4) 11/36

8 Probability 

If all the face cards are removed from a pack of 52 cards and then a card is randomly drawn then the probability of getting a ‘10 of heart’ will be  
 
1) 1 / 40
2) 2 / 49
3) 3 / 40 
4) 3 / 17 

9 Probability 

There are 50 cards maked with the numbers 1 to 50. One card is drawn at random. What is the probability that number on the card is a prime number ?

1) 3 /10
2) 1 / 5
3) 1 / 4
4) 2 /15

10 Probability 

Tickets numbered 1 to 20 are mixed up and then a ticket is drawn at random. What is the probability that the ticket drawn has a number which is a multiple of 3 or 5? 
1)  1 / 2
2)  2 / 5
3)  8/ 15
4) 9 / 20