Statistics and Probability (IMO Mathematics Olympiad (SOF) Class 9): Questions 71  77 of 101
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Question number: 71
» Statistics and Probability
Question
Cards marked with the numbers 2 to 101 are placed in a box and mixed thoroughly. One card is drawn from this bag. The probability that the number which is a perfect square is ________
Choices
Choice (4)  Response  

a. 


b. 


c. 


d. 


Question number: 72
» Statistics and Probability
Question
A card is drawn at random from a well shuffled pack of 52 cards. The probability that the cards drawn in neither a red card nor a queen are ________
Choices
Choice (4)  Response  

a. 


b. 


c. 


d. 


Question number: 73
» Statistics and Probability
Question
Two dice are thrown simultaneously. The odds against getting the sum 6 is________
Choices
Choice (4)  Response  

a. 


b. 


c. 


d. 


Question number: 74
» Statistics and Probability
Question
Two coins are tossed simultaneously. The probability of getting at two head is ________
Choices
Choice (4)  Response  

a. 


b. 


c. 


d.  0 

Question number: 75
» Statistics and Probability
Question
The average of 9 numbers is 8. What should be added as 10^{th} number to make the average 9?
Choices
Choice (4)  Response  

a.  10 

b.  72 

c.  90 

d.  18 

Question number: 76
» Statistics and Probability
Question
In a class test, in mathematics, 10 students scored 75 marks, 12 students scored 60 marks, 8 scored 40 marks and 3 scored 30 marks. The mean of their score is (approximately) ________
Choices
Choice (4)  Response  

a.  56 marks 

b.  54 marks 

c.  15 marks 

d.  57 marks 

Question number: 77
» Statistics and Probability
Question
A box contains 8 balls out of which x are black. If one ball is drawn at random from the box, what is the probability that it will be a black ball? If 4 more black balls are put in the box, the probability of drawing a black ball is now double of what is was before, then x is________
Choices
Choice (4)  Response  

a.  3 

b.  2 

c.  9 

d.  6 
