Sum of Probabilities

Q.

In a family of 3 children, find the probability of having at least one boy.

Q.

The probability of an event occurring is 0.7. The probability of that event not occuring is __.

Q.

What is the probability of guessing a three digit number correctly in one guess?

Q.

The sum of probabilities of all outcomes in an experiment is__.

Q.

Why does probability have to be between $0$ and $1$?

Q.

What is the probability of not picking a face card when you draw randomly from a pack of 52 cards?

Q. Which of the following cannot be the probability of an event?

(a) $\frac{2}{3}$

(b) $-1.5$

(c) $15\%$

(d) $0.7$

Q. Assertion : Two dice are thrown simultaneously. There are 11 possible outcomes and each of them has a probability $\frac{1}{11}$.
Reason : Probability of an event (E) is defined as P(E) $=\frac{Numberoffavourableoutcomes}{Totalnumberofpossibleoutcomes}$.

1. Both assertion and reason are true and reason is the correct explanation of assertion.
2. Both assertion and reason are true but reason is not the correct explanation of assertion.
3. Assertion is true but reason is false.
4. Assertion is false but reason is true.

Q.

If the probability of occurrence of an event is 0.9, then what is the probability of its non-occurrence?

Q.

There are six girls and four boys in a class. If one candidate is to be selected to take part in a competition, then which of the following is the probability of selecting a girl candidate?

1. ¹/₁₀

2. ²/₅

3. ⁷/₁₀

4. ³/₅

Q. Question 2 (ii)
Which of the following experiments have equally likely outcomes? Explain.
"A player attempts to shoot a basketball. She/he shoots or misses the shot."

Q. Question 23
Two dice are numbered 1, 2, 3, 4, 5, 6 and 1, 1, 2, 2, 3, 3, respectively. They are thrown and the sum of the numbers on them is noted. Find the probability of getting each sum from 2 to 9, separately.

Q. Question 1 (iv)
Complete the following statement:
The sum of the probabilities of all the elementary events of an experiment is ___.

Q. Which of the following cannot be a probability of an event ?

1. 0.5
2. 0.9
3. 99%
4. 1.25

Q.

Question 14 (iv)
One card is drawn from a well–shuffled deck of 52 cards. Find the probability of getting the jack of heart.

Q.

If the probability of happening of an event is $\frac{m}{n}$. The probability of event not happening is:

1. $\frac{m}{n}$

2. $\frac{n-m}{n}$

3. $1$

4. $m$

Q. If the probability of winning a game is 0.4, the probability of losing it is
(a) 0.96
(b) $\frac{1}{0.4}$
(c) 0.6
(d) none of these

Q.

If the probability of winning a game is 0.7, what is the probability of losing it?

Q.

If $P\left(E\right)$ and $P\left(\overline{E}\right)$ are the probabilities of two complementary events, then which of the following is always true?

1. $P\left(E\right)+P\left(\overline{E}\right)=0$

2. $P\left(E\right)+P\left(\overline{E}\right)=1$

3. $P\left(E\right)=P\left(\overline{E}\right)$

4. $P\left(E\right)+P\left(\overline{E}\right)=\frac{1}{2}$

Q. If the probability of winning a game is 0.3, what is the probability of losing it?

Q. Question 10.
I toss three coins together. The possible outcomes are no heads, 1 head, 2 head and 3 heads. So, I say that probability of no heads is $\frac{1}{4}$. What is wrong with this conclusion ?

Q. What is an elementary event ?

Q. Question 1 (iv)
Complete the following statement:
The sum of the probabilities of all the elementary events of an experiment is ___.

Q.

Sum of probabilities of all outcomes in an experiment is__

Q. In a race between Achilles and tortoise, people assigned probability to Achilles winning and tortoise winning. These probability pairs are listed below. How many of these pairs satisfy the axiomatic approach, assuming only two possible results are tortoise wins and Achilles wins.

1. $(\frac{1}{2},\frac{1}{2})$
2. $(\frac{-1}{2},1)$
3. $(\frac{3}{4},\frac{1}{2})$
4. $(1,0)$

Q. The sum of the probabilities of all the elementary events of an experiment is __.

1. 1
2. -1
3. greater than 1
4. 0

Q. If $P\left(E\right)=0.05$, what is the probability of 'not $E$'?

Q.

The sum of the probabilities of all elementary events is

1. 0

2. 0.5

3. 1

4. 2

Q. If the probability of winning a game is 0.7, what is the probability of losing it?

Q.

Which of the following cannot be the probability of an event?

1. 2/3

2. 3/2

3. 65%

4. 0.0009