CBSE - Probability

1 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 

2 Probability 

In a single throw of three dice, the probability of getting a total of 17 or 18 is 
 
1) 53/54
2) 51/54
3) 1/54 
4) 0 

3 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

4 Probability 

Two dice are tossed. The  probability that the  total sum is a prime number is:  
 
1) 1 / 6
2) 5 / 12
3) 1 / 2
4) 7 / 9 

5 Probability 

There are 30 cards of the same size in a bag on which natural numbers 1 to 30 are written. One card is taken out of the bag at random. Then the probability that the number on the selected card is not divisible by 3 is    
 
1) 1 / 3
2) 3 / 4
3) 2 / 3
4) 1 / 4

6 Probability 

Two cards are drawn together from a pack of 52 cards. The probability that one is  a spade and other is a heart, is :    
 
1) 3 / 20
2) 29 / 34
3) 47 / 100
4) 13 / 102 

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 

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 

9 Probability 

A die is thrown twice. The probability of the sum being odd, is
 
1) 1 / 2
2) 1 / 3
3) 1 / 4
4) 1 / 6 

10 Probability 

Out of a day’s production, which is 1000 machine  parts, 100 we re  found to be  sub-standard. The  probability that a part se le cte d at random be ing up to the  standard is
 
1) 1 / 10
2) 9 / 10
3) 2 / 10
4) 5 / 10