30
Q:

# Two brother X and Y appeared for an exam. The probability of selection of X is 1/7 and that of B is 2/9. Find the probability that both of them are selected.

 A) 1/63 B) 1/14 C) 2/63 D) 1/9

Answer:   C) 2/63

Explanation:

Let A be the event that X is selected and B is the event that Y is selected.

P(A) = 1/7,  P(B) = 2/9.

Let C be the event that both are selected.

P(C) = P(A) × P(B) as A and B are independent events:

= (1/7) × (2/9)  = 2/63

Q:

X attempts 100 questions and gets 340 marks. If for every correct answer is 4 marks and wrong answer is negative one mark, then the number of questions wrongly answered by Mr. X is:

 A) 14 B) 15 C) 12 D) 13

Answer & Explanation Answer: C) 12

Explanation:
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7 757
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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2 1275
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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8 959
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 1204
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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4 968
Q:

In the usual set notation,  =

 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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1 3401
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 1174
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 1150