RS Aggarwal 2020 2021 Solutions for Class 7 Maths Chapter 23 - Probability

Question 1:

Question 2:

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 =$\frac{\mathrm{Numbe}r \mathrm{of} \mathrm{times} \mathrm{heads} \mathrm{is} \mathrm{obtained}}{\mathrm{Total} \mathrm{number} \mathrm{of} \mathrm{trials}}$=$\frac{136}{300}=\frac{34}{75}$

(ii) Probability of getting a tail =$\frac{\mathrm{Number} \mathrm{of} \mathrm{times} \mathrm{tails} \mathrm{is} \mathrm{obtained}}{\mathrm{Total} \mathrm{number} \mathrm{of} \mathrm{trials}}$=$\frac{164}{300}=\frac{41}{75}$

Question 3:

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 =  $\frac{\mathrm{Number} \mathrm{of} \mathrm{times} 2 \mathrm{heads} \mathrm{have} \mathrm{been} \mathrm{obtained}}{\mathrm{Total} \mathrm{number} \mathrm{of} \mathrm{trials} }$ = $\frac{58}{200}=\frac{29}{100}$


(ii) Probability of getting 1 head = $\frac{\mathrm{Number} \mathrm{of} \mathrm{times} 1 \mathrm{head} \mathrm{has} \mathrm{been} \mathrm{obtained}}{\mathrm{Total} \mathrm{number} \mathrm{of} \mathrm{trials} }$ = $\frac{83}{200}$


(iii) Probability of getting 0 head =  $\frac{\mathrm{Number} \mathrm{of} \mathrm{times} \mathrm{head} \mathrm{has} \mathrm{not} \mathrm{been} \mathrm{obtained}}{\mathrm{Total} \mathrm{number} \mathrm{of} \mathrm{trials} }$ = $\frac{59}{200}$

Question 4:

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

$$\begin{gathered} \left(\mathrm{i}\right) \mathrm{Probability} \mathrm{of} \mathrm{getting} \mathrm{a} 3=\frac{\mathrm{Number} \mathrm{of} \mathrm{times} 3 \mathrm{is} \mathrm{obtained}}{\mathrm{Total} \mathrm{number} \mathrm{of} \mathrm{trials} }=\frac{18}{100}=\frac{9}{50} \\ \left(\mathrm{ii}\right) \mathrm{Probability} \mathrm{of} \mathrm{getting} \mathrm{a} 6=\frac{\mathrm{Number} \mathrm{of} \mathrm{times} 6 \mathrm{is} \mathrm{obtained}}{\mathrm{Total} \mathrm{number} \mathrm{of} \mathrm{trials} }=\frac{9}{100} \\ \left(\mathrm{iii}\right) \mathrm{Probability} \mathrm{of} \mathrm{getting} \mathrm{a} 4=\frac{\mathrm{Number} \mathrm{of} \mathrm{times} 4 \mathrm{is} \mathrm{obtained}}{\mathrm{Total} \mathrm{number} \mathrm{of} \mathrm{trials} }=\frac{15}{100}=\frac{3}{20} \\ \left(\mathrm{iv}\right) \mathrm{Probability} \mathrm{of} \mathrm{getting} \mathrm{a} 1=\frac{\mathrm{Number} \mathrm{of} \mathrm{times} 1 \mathrm{is} \mathrm{obtained}}{\mathrm{Total} \mathrm{number} \mathrm{of} \mathrm{trials} }=\frac{21}{100} \end{gathered}$$