NCERT Exemplar Solutions
Class 11 - Mathematics - Chapter 16: PROBABILITY
Objective Type Question

Choose the correct answer from the given four options:

Question.  18

In a non-leap year, the probability of having 53 Tuesdays or 53 Wednesdays is

(a)

\(\tfrac{1}{7}\)

(b)

\(\tfrac{2}{7}\)

(c)

\(\tfrac{3}{7}\)

(d)

none of these

Question.  19

Three numbers are chosen from 1 to 20. Find the probability that they are not consecutive

(a)

\(\tfrac{186}{190}\)

(b)

\(\tfrac{187}{190}\)

(c)

\(\tfrac{188}{190}\)

(d)

\(\tfrac{18}{\binom{20}{3}}\)

Question.  20

While shuffling a pack of 52 playing cards, 2 are accidentally dropped. Find the probability that the missing cards are of different colours

(a)

\(\tfrac{29}{52}\)

(b)

\(\tfrac{1}{2}\)

(c)

\(\tfrac{26}{51}\)

(d)

\(\tfrac{27}{51}\)

Question.  21

Seven persons are to be seated in a row. The probability that two particular persons sit next to each other is

(a)

\(\tfrac{1}{3}\)

(b)

\(\tfrac{1}{6}\)

(c)

\(\tfrac{2}{7}\)

(d)

\(\tfrac{1}{2}\)

Question.  22

Without repetition of the digits, four-digit numbers are formed with the digits 0, 2, 3, 5. The probability of such a number being divisible by 5 is

(a)

\(\tfrac{1}{5}\)

(b)

\(\tfrac{4}{5}\)

(c)

\(\tfrac{1}{30}\)

(d)

\(\tfrac{5}{9}\)

Question.  23

If A and B are mutually exclusive events, then

(a)

\(P(A) \le P(\overline{B})\)

(b)

\(P(A) \ge P(\overline{B})\)

(c)

\(P(A) < P(\overline{B})\)

(d)

none of these

Question.  24

If \(P(A \cup B) = P(A \cap B)\) for any two events A and B, then

(a)

\(P(A) = P(B)\)

(b)

\(P(A) > P(B)\)

(c)

\(P(A) < P(B)\)

(d)

none of these

Question.  25

Six boys and six girls sit in a row at random. The probability that all the girls sit together is

(a)

\(\tfrac{1}{432}\)

(b)

\(\tfrac{12}{431}\)

(c)

\(\tfrac{1}{132}\)

(d)

none of these

Question.  26

A single letter is selected at random from the word "PROBABILITY." The probability that it is a vowel is

(a)

\(\tfrac{1}{3}\)

(b)

\(\tfrac{4}{11}\)

(c)

\(\tfrac{2}{11}\)

(d)

\(\tfrac{3}{11}\)

Question.  27

If the probabilities for A to fail is 0.2 and for B is 0.3, then the probability that either A or B fails is

(a)

> 0.5

(b)

0.5

(c)

\(\le 0.5\)

(d)

0

Question.  28

The probability that at least one of the events A and B occurs is 0.6. If A and B occur simultaneously with probability 0.2, then \(P(\overline{A}) + P(\overline{B})\) is

(a)

0.4

(b)

0.8

(c)

1.2

(d)

1.6

Question.  29

If M and N are any two events, the probability that at least one of them occurs is

(a)

\(P(M)+P(N)-2P(M\cap N)\)

(b)

\(P(M)+P(N)-P(M\cap N)\)

(c)

\(P(M)+P(N)+P(M\cap N)\)

(d)

\(P(M)+P(N)+2P(M\cap N)\)

NCERT Exemplar Solutions Class 11 – Mathematics – Chapter 16: PROBABILITY – Objective Type Question | Detailed Answers