# Probability Quiz Set 012

### Question 1

48 defective pens are accidentally mixed with 56 good ones. It is not possible to just look at a pen and tell whether it is defective or not. One pen is taken out at random. What is the probability that it is a defective pen?

A

\${6/13}\$.

B

\$50/104\$.

C

\$7/104\$.

D

\$11/104\$.

Soln.
Ans: a

Out of the total number of pens = 104, the chances favoring defective pen are 48. So the probability is 48/104 = \${6/13}\$.

### Question 2

9 tumblers are lying inverted on a table. 7 of them contain balls, but 2 of them are empty. What is the probability of getting a ball if one of the tumblers is opened randomly?

A

\${7/9}\$.

B

\$8/9\$.

C

\$9/9\$.

D

\$12/9\$.

Soln.
Ans: a

Chances favoring a ball are 7, whereas the total chances are 9. The probability is 7/9 = \${7/9}\$.

### Question 3

A bag contains 2 Red, 4 Blue and 7 Green marbles. What is the probability of drawing a Red marble if 2 marbles are drawn out randomly?

A

\${23/78}\$.

B

\$7/13\$.

C

D

\$28/78\$.

Soln.
Ans: a

Total number of marbles is 13. Combinations of 2 marbles that are possible = 13C2 = \${13 × 12}/2\$ = 78. If one of the two balls is red, then red + red is one possibility, and 2 × (4 + 7) are the other possibilities. So total favorable outcomes = 1 + 2 × 11 = 23, and the probability is 23/78 = \${23/78}\$.

### Question 4

Karmjeet and Sham are friends. What is the probability that both will have different birthdays, ignoring a leap year?

A

\${364/365}\$.

B

\$21/365\$.

C

\$365/365\$.

D

\$369/365\$.

Soln.
Ans: a

The birthday of second friend has 365 outcomes. If it is not to match the birthday of the first friend, the number of favorable outcomes is 365 - 1 = 364. So probability is 364/365.

### Question 5

A box contains 5 pink, 2 maroon and 6 cyan balls. What is the probability of drawing a ball that is neither maroon nor pink?

A

\${6/13}\$.

B

\$7/13\$.

C

\$7/78\$.

D

\$11/78\$.

Soln.
Ans: a

Total number of marbles is 13. We have to basically find the probability of picking a cyan ball, for which 6 chances are favorable. So probability = 6/13 = \${6/13}\$. This Blog Post/Article "Probability Quiz Set 012" by Parveen (Hoven) is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
Updated on 2020-02-07. Published on: 2016-05-08