# Probability Quiz Set 020

### Question 1

A box contains 6 cyan, 3 pink and 8 orange marbles. What is the probability of drawing a orange marble if 2 marbles are drawn out randomly?

A

\${25/34}\$.

B

\$8/17\$.

C

\$26/136\$.

D

\$30/136\$.

Soln.
Ans: a

Total number of marbles is 17. Combinations of 2 marbles that are possible = 17C2 = \${17 × 16}/2\$ = 136. If one of the two balls is orange, then both balls will be orange in 8C2 = \${8 × (8 - 1)}/2\$ = 28 ways. The number of ways in which non-orange can be drawn out are 8 × (6 + 3). So total favorable outcomes = 28 + 8 × 9 = 100, and the probability is 100/136 = \${25/34}\$.

### Question 2

One card is drawn at random from a pack of 52 cards. What is the probability that it is either a Jack, or a Queen or a King only?

A

3/13.

B

5/26.

C

1/13.

D

8/52.

Soln.
Ans: a

There are 12 such cards in the entire deck of 52 cards, so the required probability is 12/52 = 3/13.

### Question 3

If P(E) = 0.54, then what is the probability of non-occurrence of E?

A

0.46.

B

0.54.

C

0.5.

D

0.25.

Soln.
Ans: a

P(E) + P(non-occurrence of E) is always = 1. So P(non-occurrence of E) = 1 - P(E) = 0.46.

### Question 4

What is the probability of getting a sum of 2 from two throws of a dice?

A

1/18.

B

1/3.

C

2/3.

D

1/6.

Soln.
Ans: a

Total outcomes = 36. Favorable are 2, which are: (1, 1), (1, 1). Probability = 2/36 = 1/18.

### Question 5

Two players, A and B, play a game. It is known that probability of A's victory is 0.2. What is the probability of B's victory?

A

0.8.

B

0.2.

C

0.5.

D

0.25.

Soln.
Ans: a

One of the two is going to win. Probability of A's defeat is 1 - 0.2 = 0.8, which is the probability of B's victory. 