# Probability Quiz Set 015

### Question 1

A bag contains lemon flavored candies only. Malini takes out a candy without looking into the bag. What is the probability that she takes out an orange flavored candy?

A

0.

B

1.

C

0.5.

D

2.

Soln.
Ans: a

The bag contains lemon flavored candies only, so the probability of orange flavored candy being taken out is zero.

### Question 2

What is the probability of getting a sum of 7 from two throws of a dice?

A

1/6.

B

1/3.

C

6/7.

D

7/6.

Soln.
Ans: a

Total outcomes = 36. Favorable are 6, which are: (1, 6), (6, 1), (2, 5), (5, 2), (3, 4), (4, 3). Probability = 6/36 = 1/6.

### Question 3

A class has 6 boys and 5 girls. What is the probability of choosing 1 boy and 2 girls?

A

\${4/11}\$.

B

\$7/11\$.

C

\$5/11\$.

D

\$9/11\$.

Soln.
Ans: a

Three students have to be picked. Total number of ways = 11C3 = \${11 × 10 × 9}/{3 × 2 × 1} = \$165. Number of ways of picking 1 boy and 2 girls = 6C1 × 5C2 = 60. So probability = \$60/165\$ = \${4/11}\$.

### Question 4

Three unbiased coins are tossed. What is the probability of getting at most two tails?

A

7/8.

B

3/8.

C

1/8.

D

5/8.

Soln.
Ans: a

Three coins will give 8 possibilities = 2 × 2 × 2. At most two tails means 1 or 2 tails. We will not get this only when all heads come, which is possible only once. So 8 - 1 = 7 chances are favorable. The probability = 7/8.

### Question 5

A box contains 2 navy, 4 red and 6 sky blue marbles. What is the probability of drawing a marble that is not sky blue if 2 marbles are drawn out randomly?

A

\${5/22}\$.

B

\$6/12\$.

C

\$6/66\$.

D

\$10/66\$.

Soln.
Ans: a

Total number of marbles is 12. Combinations of 2 marbles that are possible = 12C2 = \${12 × 11}/2\$ = 66. Chances of drawing a non-sky blue ball are 6C2 = \$(6 × (6 - 1))/2\$ = 15. So probability = 15/66 = \${5/22}\$. 