CBSE - Probability

1 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 

2 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

3 Probability 

 Three unbiased coins are tossed together. Then the probability of getting at least one head and one tail is   
 
1) 1 / 4
2) 1
3) 3 / 4 
4) 0 

4 Probability 

Box A contains 30% first grade articles. Box B contains 40% first grade articles. One article is draw from each box. Then the probability that both articles drawn are first grade is   
 
1) 1 / 25
2) 3 / 25
3) 7 / 25 
4) 9 / 25 

5 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

6 Probability 

A die is thrown twice. Then the probability that 5 will come up at least once is  
 
1) 11/ 36
2) 7 / 36
3) 5 / 36 
4) 0 

7 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

8 Probability 

The king, queen and jack of hearts are removed from a deck of 52 playing cards and then wellshuffled. One card is selected from the remaining cards. Then the probability of getting a king is  
 
1)  1 / 49
2)  2 / 49
3)  3 / 49 
4) 1 

9 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 

10 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