Exercise 4.2 (Revised) - Chapter 5 - Data Handling - Ncert Solutions class 8 - Maths

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Chapter 4 - Data Handling | NCERT Solutions for Class 8 Maths

Ex 4.2 Question 1.

List the outcomes you can see in these experiments.
(a) Spinning a wheel

(b) Tossing two coins together

Answer.

(a) There are four letters A, B, C and D in a spinning wheel. So there are 4 outcomes.
(b) When two coins are tossed together. There are four possible outcomes $\mathrm{HH}, \mathrm{HT}, \mathrm{TH}, \mathrm{TT}$.
(Here HT means head on first coin and tail on second coin and so on.)
Ex 4.2 Question 2.

When a die is thrown, list the outcomes of an event of getting:
(i) (a) a prime number
(b) not a prime number
(ii) (a) a number greater than 5
(b) a number not greater than 5

Answer.

(i) (a) Outcomes of event of getting a prime number are 2, 3 and 5 .
(b) Outcomes of event of not getting a prime number are 1, 4 and 6 .

(ii) (a) Outcomes of event of getting a number greater than 5 is 6 .
(b) Outcomes of event of not getting a number greater than 5 are 1, 2, 3, 4 and 5 .
Ex 4.2 Question 3.

Find the:
(a) Probability of the pointer stopping on $D$ in (Question 1 (a)).
(b) Probability of getting an ace from a well shuffled deck of 52 playing cards.
(c) Probability of getting a red apple. (See figure below)

Answer.

(a) In a spinning wheel, there are five pointers A, A, B, C, D. So there are five outcomes. Pointer stops at D which is one outcome.

So the probability of the pointer stopping on $\mathrm{D}=\frac{1}{5}$
(b) There are 4 aces in a deck of 52 playing cards. So, there are four events of getting an ace.

So, probability of getting an ace $=\frac{4}{52}=\frac{1}{13}$
(c) Total number of apples $=7$

Number of red apples $=4$

Probability of getting red apple $=\frac{4}{7}$
Ex 4.2 Question 4.

Numbers 1 to 10 are written on ten separate slips (one number on one slip), kept in a box and mixed well. One slip is chosen from the box without looking into it. What is the probability of:
(i) getting a number 6 .
(ii) getting a number less than 6 .
(iii) getting a number greater than 6 .
(iv) getting a 1-digit number.

Answer.

(i) Outcome of getting a number 6 from ten separate slips is one.
Therefore, probability of getting a number $6=\frac{1}{10}$
(ii) Numbers less than 6 are 1, 2, 3, 4 and 5 which are five. So there are 5 outcomes.

Therefore, probability of getting a number less than $6=\frac{5}{10}=\frac{1}{2}$
(iii) Number greater than 6 out of ten that are 7, 8, 9, 10. So there are 4 possible outcomes.

Therefore, probability of getting a number greater than $6=\frac{4}{10}=\frac{2}{5}$

(iv) One digit numbers are $1,2,3,4,5,6,7,8,9$ out of ten.

Therefore, probability of getting a 1-digit number $=\frac{9}{10}$
Ex 4.2 Question 5.

If you have a spinning wheel with 3 green sectors, 1 blue sector and 1 red sector, what is the probability of getting a green sector? What is the probability of getting a noneblue sector?

Answer.

There are five sectors. Three sectors are green out of five sectors.
Therefore, probability of getting a green sector $=\frac{3}{5}$
There is one blue sector out of five sectors.

Non-blue sectors $=5-1=4$ sectors
Therefore, probability of getting a non-blue sector $=\frac{4}{5}$
Ex 4.2 Question 6.

Find the probability of the events given in Question 2.

Answer.

When a die is thrown, there are total six outcomes, i.e., 1, 2, 3, 4, 5 and 6 .
(i) (a) 2, 3, 5 are prime numbers. So there are 3 outcomes out of 6 .

Therefore, probability of getting a prime number $=\frac{3}{6}=\frac{1}{2}$
(b) 1, 4, 6 are not the prime numbers. So there are 3 outcomes out of 6 .

Therefore, probability of getting a prime number $=\frac{3}{6}=\frac{1}{2}$
(ii) (a) Only 6 is greater than 5 . So there is one outcome out of 6 .

Therefore, probability of getting a number greater than $5=\frac{1}{6}$
(b) Numbers not greater than 5 are 1, 2, 3, 4 and 5 . So there are 5 outcomes out of 6 .

Therefore, probability of not getting a number greater than $5=\frac{5}{6}$