Statistics & Probability (IMO Mathematics Olympiad Class 10): Questions 36  41 of 80
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Question number: 36
» Statistics & Probability
Question
The mean of 20 observations is. if each observation is multiplied by 2, then what is the new mean?
Choices
Choice (4)  Response  

a.  60 

b.  30 

c.  70 

d.  50 

Question number: 37
» Statistics & Probability
Question
A box contains 40 balls of two different colours, out of which x are black. One ball is drawn at random. If 20 more black balls are put in the box, the probability of drawing a black ball now will be double that of the previous probability of drawing a black ball. Then, the value of x is ________
Choices
Choice (4)  Response  

a.  15 

b.  14 

c.  12 

d.  10 

Question number: 38
» Statistics & Probability
Question
A Motor maintains an average speed of 70 km/hr while going from P to Q and maintains an average speed of 85 km/hr while coming back from Q to P. the average speed of the motor is ________.
Choices
Choice (4)  Response  

a. 


b. 


c. 


d. 


Question number: 39
» Statistics & Probability
Question
Two dice are thrown simultaneously. The probability of getting a total 5, 6 or 7 is ________
Choices
Choice (4)  Response  

a. 


b. 


c. 


d. 


Question number: 40
» Statistics & Probability
Question
The mean of five numbers is 18. If one number is excluded, then their mean is 16, the excluded number is ________
Choices
Choice (4)  Response  

a.  25 

b.  26 

c.  28 

d.  24 

Question number: 41
» Statistics & Probability
Question
The average age of 5 teachers is 28 years. If one teacher is excluded the mean gets reduced by 2 years. The age of the excluded teacher is ________
Choices
Choice (4)  Response  

a.  33 years 

b.  36 years 

c.  35 years 

d.  26 years 
