Hello Aspirants. Welcome to Online Maths in AffairsCloud.com. Here we are creating question sample in **Probability**, which is common for all the competitive exams. We have included Some questions that are repeatedly asked in exams !!

**A box contain 4 white, 3 blue and 2 black marbles. If 2 marbles are picked up at random. What is the probability that both of them are black ?**

A.20

B.1/36

C.1/22

D.36

E.None of theseAnswer –**B.1/36**

**Explanation :**

P = 2C2/9C2 = 1/36**An urn contains 6 maroon, 3 pink and 4 white balls. If three balls are drawn What is the probability that all are pink or white?**

A.11/328

B.7/212

C.5/286

D.9/127

E.None of theseAnswer –**C.5/286**

**Explanation :**

P =3C3/13C3 + 4C3/13C3

= 1/286 + 4/286 = 5/26**From a pack of 52 cards 3 cards are drawn one by one without replacements.Find the probability that both of them are king ?**

A.132/1338

B.32/2340

C.1/5525

D.4/2755

E.None of theseAnswer –**C.1/5525**

**Explanation :**

4/52*3/51*2/50 = 24/132600 = 4/22100 = 1/5525**If two dice are thrown simultaneously, what is the probability that the sum of the numbers appeared is less than seven?**

A.5/12

B.7/12

C.6/17

D.13/27

E.None of theseAnswer –**A.5/12**

**Explanation :**

Sum of the numbers can be 1,2, 3, 4, 5, and 6.

1+2= 3

1+3 = 4

1+4 = 5

1+5 = 6

2+3 = 5

3+2 = 5

2+4 = 6

4+2 = 6……..etc

n (E) = 15, n (S) = 36

P (E) =15/36 = 5/12**A box contains 5 white, 4 green, 2 blue and 3 black marbles. If 2 marbles are drawn at random, what is the probability that both are green or at least one is green ?**

A.46/91

B.32/97

C.16/75

D.1/54

E.None of theseAnswer –**A.46/91**

**Explanation :**

4C2+(4C1*10C1)/12C2 = 6+40/91 = 46/91**In a shelf, there are 7 Banking awareness, 6 English and 5 GK books. One book is picked up randomly. What is the probability that it is neither in Banking awareness nor in GK ?**

A.1/13

B.2/17

C.1/3

D.12/27

E.None of theseAnswer –**C.1/3**

**Explanation :**

P = 6/18 = 1/3**A suitcase contains 4 blue shirts, 5 red shirts and 3 white shirts.If 4 shirts are drawn what is the probability that exactly one of them is blue ?**

A.113/218

B.14/167

C.123/234

D.224/495

E.None of theseAnswer –**D.224/495**

**Explanation :**

P = 4C1*8C3/12C4 = 4*56/495 = 224/495**A bag contains 4 white, 8 black and 6 blue balls. If two balls are drawn at random, find the probability of both the balls being black?**

A.22/137

B.14/123

C.28/253

D.7/105

E.None of theseAnswer –**C.28/253**

**Explanation :**

n(S) = 18C2 = 153

There are eight black balls, out of which two balls are drawn in 8C2 ways.

n(E) = 28

P(E) = 28 /153 = 28/153**The ratio of the number of girls to the number of boys is the 5 : 2 in a class of 21 students. A group of three students is to to be selected at random amongst them. What is the probability that the selected group of students contain one boy and two girls?**

A.45/266

B.32/343

C.120/217

D.46/267

E.None of theseAnswer –**A.45/266**

**Explanation :**

5:2 = 15+6 = 21

n(S) = 21C3 = 1330

n(E) = 15C1 × 6C2 = 15 × 15 = 225

P = 225/1330 = 45/266**A bag 5 red and 8 white balls.Two draws of three balls each are made.What is the probability that the balls were pink in the first draw and white in the second draw ?**

A.23/345

B.140/20449

C.20440/110

D.230/23454

E.None of theseAnswer –**B.140/20449**

**Explanation :**

5C3/13C3 *8C3/13C3 = 60/286*56/286 = 140/20449

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