Probability Quiz Set 002

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Question 1

A class has 7 boys and 2 girls. What is the probability of choosing 1 boy and 2 girls?

 A

${1/12}$.

 B

$8/9$.

 C

$2/12$.

 D

$6/12$.

Soln.
Ans: a

Three students have to be picked. Total number of ways = 9C3 = ${9 × 8 × 7}/{3 × 2 × 1} = $84. Number of ways of picking 1 boy and 2 girls = 7C1 × 2C2 = 7. So probability = $7/84$ = ${1/12}$.


Question 2

A dice is thrown once. What is the probability that we get a number greater than 4?

 A

1/3.

 B

2/3.

 C

5/6.

 D

1.

Soln.
Ans: a

Total outcomes = 6. Favorable outcomes are 2: getting a 5 or 6. The required probability is 2/6 = 1/3.


Question 3

What is the probability of getting a head when a coin is tossed in the air?

 A

1.

 B

1/2.

 C

1/4.

 D

0.

Soln.
Ans: b

Total outcomes are 2, H or T. The number of favorable chances for heads is 1. So probability is 1/2.


Question 4

A box contains 82 red balls and an unknown number of blue balls. If the probability of drawing a blue ball is 2 times the probability of drawing a red ball, then how many blue balls are there in the box?

 A

164.

 B

169.

 C

159.

 D

174.

Soln.
Ans: a

Let the number of blue balls be x. Chances of drawing a blue ball are $x/{x + 82}$ = 2 × $82/{x + 82}$, which gives x = 2 × 82 = 164.


Question 5

A class has 5 boys and 3 girls. What is the probability of choosing 1 boy and 2 girls?

 A

${15/56}$.

 B

$6/8$.

 C

$16/56$.

 D

$20/56$.

Soln.
Ans: a

Three students have to be picked. Total number of ways = 8C3 = ${8 × 7 × 6}/{3 × 2 × 1} = $56. Number of ways of picking 1 boy and 2 girls = 5C1 × 3C2 = 15. So probability = $15/56$ = ${15/56}$.


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Creative Commons License
This Blog Post/Article "Probability Quiz Set 002" by Parveen (Hoven) is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
Updated on 2017-06-24.

Posted by Parveen(Hoven),
Aptitude Trainer


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