Daily Practice Problems

Class 11 Maths

Probability

Class 11 Maths

Probability

**Question 1:**

Two coins are thrown together. What is the sample space?

**Question 2:**

Two dice are thrown simultaneously. Find the probability of getting a total of 9.

**Question 3:**

Three coins are tossed once. The probability of getting at most 2 heads is ________.

**Question 4:**

The probability of getting 53 Sundays in a leap year is _____.

**Question 5:**

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

girls sit alternatively is _____.

**Question 6:**

If P(AUB) = 0.6 and P(A B) =0.2 then P(A ̅) + P(B ̅) is _____.

**Question 7:**

A single letter is selected at random from the word PROBABILITY. The

probability that it is a vowel is _____.

**Question 8:**

Out of 100 students, two sections of 40 and 60 are formed. If you and your friend are among the 100 students, what is the probability that you both enter in the same section?

**Question 9:**

One card is drawn from a set of 17 cards numbered 1 to 17. Find the probability that the number is divisible by 3 or 7.

**Question 10:**

There are four machines and it is known that exactly two of them are faulty. They are tested, one by one, in a random order till both the faulty machines are identified. Then the probability that only two tests are needed is _________.

**Question 11:**

A couple has two children. The probability that both children are females if it is known that the elder child is a female is _________.

**Question 12:**

A coin is tossed and a die is thrown. Find the sample space.

**Question 13:**

Two dice are thrown. The events A, B and C are as follows:

A: getting an even number on the first die.

B: getting an odd number on the first die.

C: getting the sum of the numbers on the dice ≤ 5.

State true or false: (give reason for your answer)

(i) A and B are mutually exclusive

(ii) A = B′

(iii) A′, B′, C are mutually exclusive and exhaustive.

**Question 14:**

If E and F are events such that P(E) = 14 , P(F) = 12 and P(E and F) = 18 , find

(i) P(E or F), (ii) P(not E and not F).

**Question 15:**

On his vacation, Rahul visits four cities (A, B, C, and D) in a random order. The probability that he visits A first and B last is _________.

**Question 16:**

In a large metropolitan area, the probabilities are 0.87, 0.36, 0.30 that a family (randomly chosen for a sample survey) owns a colour television set, a black and white television set, or both kinds of sets. What is the probability that a family owns either anyone or both kinds of sets?

**Question 17:**

The probability that a person visiting a zoo will see the giraffe is 0.72, the probability that he will see the bears is 0.84. Is it possible that the probability that he will see both is 0.52?

**Question 18:**

Is it possible that the probabilities that a typist will make 0, 1, 2, 3, 4, 5 or more mistakes in typing a report are, respectively, 0.12, 0.25, 0.36, 0.14, 0.08, 0.11.

**Question 19:**

Two dice are thrown the events A, B, C are as follows:

A: Getting an odd number on the first die.

B: Getting a total of 7 on the two dice.

C: Getting a total of greater than or equal to 8 on the two dice.

Then AUB is equal to _________.

**Question 20:**

Two numbers are chosen from {1, 2, 3, 4, 5, 6} one after another without replacement. Find the probability that the smaller of the two is less than 4.

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