RS Aggarwal 2019,2020 solution class 7 chapter 23 Probability Exercise 23

Exercise 23

Page-283

Question 1:

A coin is tossed 300 times and we get head : 136 times and tail : 164 times.
When a coin is tossed at random, What is the probability of getting (i) a head, (ii) a tail?

Answer 1:

Total number of trials = 300
Number of times a head is obtained = 136
Number of times a tail is obtained= 164

(i) Probability of getting head =Number of times heads is obtainedTotal number of trials=136300=3475

(ii) Probability of getting a tail =Number of times tails is obtainedTotal number of trials=164300=4175

Question 2:

Two coins are tossed simultaneously 200 times and we get two heads: 58 times, one head: 83 times: 0 head: 59 times.
When two coins are tossed at random, what is the probability of getting (i) 2 heads, (ii) 1 head, (iii) 0 head?

Answer 2:

Total number of trials = 200
Number of times 2 heads are obtained = 58
Number of times one head is obtained  = 83
Number of times no head is obtained = 59

(i) Probability of getting 2 heads =  Number of times 2 heads have been obtainedTotal number of trials  = 58200=29100


(ii) Probability of getting 1 head = Number of times 1 head has been obtainedTotal number of trials  = 83200


(iii) Probability of getting 0 head =  Number of times head has not been obtainedTotal number of trials  = 59200

Question 3:

A dice is thrown 100 times and the outcomes are noted as given below:

Outcome 1 2 3 4 5 6
Frequency 21 14 18 15 23 9

When a dice is thrown at random, what is the probability of getting a (i) 3, (ii) 6, (iii) 6, (iv) 1?

Answer 3:

Total number of trials = 100
Number of times 3 is obtained = 18
Number of times 6 is obtained = 9
Number of times 4 is obtained = 15
Number of times 1 is obtained =  21

(i) Probability of getting a 3=Number of times 3 is obtainedTotal number of trials =18100=950(ii) Probability of getting a 6=Number of times 6 is obtainedTotal number of trials =9100(iii) Probability of getting a 4=Number of times 4 is obtainedTotal number of trials =15100=320(iv) Probability of getting a 1=Number of times 1 is obtainedTotal number of trials =21100

Question 4:

In a survey of 100 ladies it was found that 36 like coffee while 64 dislike it.
Out of these ladies, one is chosen at random. What is the probability that the chosen lady (i) likes coffee, (ii) dislikes coffee?

Answer 4:

Total number of ladies surveyed = 100
Ladies who like coffee = 36
Ladies who do not like coffee = 64

(i) Probability of choosing a lady who likes coffee=Number of ladies who like coffeeTotal number of ladies =36100=925(ii) Probability of choosing a lady who dislikes coffee=Number of ladies who dislike coffeeTotal number of ladies =64100=1625

No comments:

Post a Comment

Contact Form

Name

Email *

Message *