6
Q:

The probabilities that A and B will tell the truth are 2 / 3 and 4 / 5 respectively . What is the probability that they agree with each other ?

A) 3/5 B) 1/3
C) 2/5 D) 3/4

Answer:   A) 3/5



Explanation:

Let A be the event of A will tell truth. B be the event of B tell truth

 

 P(A)=23,P(Ac)=1-P(A)=13

 

 

 

P(B)=45,P(Bc)=1-P(B)=15 

 

When both agree then they say true or they say false together, that is 

 

 AB or AcBc

 

 

 

Also these events will be mutually exclusive :

 

 P(AB)+P(AcBc)=P(A)P(B)P(C)=23*45+13*15=35

Q:

If the standard deviation of 0, 1, 2, 3 ......... 9 is K, then the standard deviation of 10, 11, 12, 13 ........... 19 will be:

 

A) K+1 B) K
C) K+4 D) K+8
 
Answer & Explanation Answer: B) K

Explanation:
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1 764
Q:

The standard deviation of the set {10, 11, 12, 9, 8} is

A) 1 B) √2
C) 2 D) 2√2
 
Answer & Explanation Answer: B) √2

Explanation:
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6 676
Q:

Find the range of the data 2, 1, 2, 3, 5, 4, 7, 3, 5, 2, 4.

A) 5 B) 4
C) 3 D) 6
 
Answer & Explanation Answer: D) 6

Explanation:
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1 661
Q:

Find the median, mode and mean of 9, 5, 8, 9, 9, 7, 8, 9, 8.

A) 9, 9, 9 B) 9, 8, 9
C) 8, 9, 8 D) 8, 9, 9
 
Answer & Explanation Answer: C) 8, 9, 8

Explanation:
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2 619
Q:

In the usual set notation, A  (B  C) =

 

 

A) A∪B∪A∪C B) A∩B∪A∩C
C) A∪B∩A∪C D) A∪B∩A∩C
 
Answer & Explanation Answer: C) A∪B∩A∪C

Explanation:
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0 2221
Q:

Find the range and mode of the data 17, 18, 28, 19, 16, 18, 17, 29, 18

A) 12 and 18 B) 13 and 18
C) 12 and 17 D) 11 and 17
 
Answer & Explanation Answer: B) 13 and 18

Explanation:
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1 774
Q:

Find the standard deviation of {11, 7, 10,13, 9}

A) 1 B) 2
C) 4 D) 5
 
Answer & Explanation Answer: B) 2

Explanation:
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2 797
Q:

A table tennis player, lost 12 games out of 18 games played. Calculate the games won in terms of decimal.

A) 0.667 B) 0.067
C) 0.50 D) 0.333
 
Answer & Explanation Answer: D) 0.333

Explanation:
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3 849