Hello Aspirants.

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

**Bank PO Level Questions** :-

**A box contains 27 marbles some are blue and others are green. If a marble is drawn at random from the box, the probability that it is blue is 1/3. Then how many number of green marbles in the box?**

A. 10

B. 15

C. 14

D. 18

Answer –**D. 18**

**Explanation :**

Blue marble – x

xc1/27c1 = 1/3

x/27=1/3 —> x=27/3=9

No of green marbles = Total – Blue marble =27-9=18**In a bag there are 4 white, 4 red and 2 green balls. Two balls are drawn at random.What is the probability that at least one ball is of red colour?**

A. 4/3

B. 7/3

C. 1/3

D. 2/3

Answer –**D. 2/3**

**Explanation :**

Total Balls =10

Other than red ball = 6c2

6c2/10c2=1/3 —> 1-1/3 = 2/3**Sahil has two bags (A & B) that contain green and blue balls.In the Bag ‘A’ there are 6 green and 8 blue balls and in the Bag ‘B’ there are 6 green and 6 blue balls. One ball is drawn out from any of these two bags. What is the probability that the ball drawn is blue?**

A. 15/28

B. 13/28

C. 17/28

D. 23/28

Answer –**A. 15/28**

**Explanation :**

Total balls in A bag = 14, Total balls in A bag = 12

A bag = 1/2(8c1/14c1) = 2/7

B bag = 1/2(6c1/12c1) = 1/4 —> total Probability = 2/7 + 1/4 =15/28**In an examination, there are three sections namely Reasoning, Maths and English. Reasoning part contains 4 questions. There are 5 questions in maths section and 6 questions in English section. If three questions are selected randomly from the list of questions then what is the probability that all of them are from maths?**

A. 7/91

B. 8/91

C. 2/91

D. 4/91

Answer –**C. 2/91**

**Explanation :**

Total no of questions= 15

Probability = 5c3/15c3 = 2/91**A basket contains 5 red 4 blue 3 green marbles. If three marbles picked up random, What is the probability that either all are green or all are red?**

A. 1/20

B. 7/20

C. 3/20

D. 9/20

Answer –**A. 1/20**

**Explanation :**

Total Marbles = 12

Either all are green or all are red = 5c3 + 3c3

probability = 5c3 + 3c3/12c3 = 11/220 = 1/20**A basket contains 5 red 4 blue 3 green marbles. If three marbles picked up random, What is the probability that at least one is blue?**

A. 41/55

B. 53/55

C. 47/55

D. 49/55

Answer –**A. 41/55**

**Explanation :**

Total Marbles = 12

other than blue 8c3 / 12c3 = 14/55

probability = 1-14/55 = 41/55**A basket contains 5 red 4 blue 3 green marbles. If two marbles picked up random, What is the probability that both are red?**

A. 4/33

B. 5/33

C. 7/33

D. 8/33

Answer –**B. 5/33**

**Explanation :**

Total Marbles = 12

Probability = 5c2 / 12c2 = 5/33**A bag contains 5 red caps, 4 blue caps, 3 yellow caps and 2 green caps.If three caps are picked at random, what is the probability that two are red and one is green?**

A. 22/55

B. 15/81

C. 10/91

D. 5/91

Answer –**D. 5/91**

**Explanation :**

Total caps = 14

Probability = 5c2 * 2c1/ 14c3 = 5/91**A bag contains 5 red caps, 4 blue caps, 3 yellow caps and 2 green caps. If four caps are picked at random, what is the probability that two are red, one is blue and one is green?**

A. 22/1001

B. 80/1001

C. 21/1001

D. 55/1001

Answer –**B. 80/1001**

**Explanation :**

Total caps = 14

Probability = 5c2 * 4c1 * 2c1 / 14c4 = 80/1001**A bag contains 2 red caps, 4 blue caps, 3 yellow caps and 5 green caps. If three caps are picked at random, what is the probability that none is green?**

A. 2/13

B. 3/13

C. 1/13

D. 5/13

Answer –**B. 3/13**

**Explanation :**

Total caps = 14

Probability = 5c0 * 9c3/ 14c3 = 3/13

**Note:** Dear Readers if you have any doubt in any chapter in Quants you can ask here. We will clear your doubts

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