7th Class Mathematics Comparing Quantities Percentage


Category : 7th Class

*     Introduction                


Percentage is a fraction whose denominator is 100. The numerator of the such fraction is called the rate percent. For example 15 percent means \[\frac{15}{100}\] and denoted by 15 %.  


*     Percentage          


a % means \[\frac{a}{100}\] and simplify it. e.g.  \[45%=\frac{45}{100}=\frac{9}{20}\]                

For conversion of fraction \[\frac{p}{q}\] as percentage, we simply multiply it by 100 and put the sign of % or mathematically we can write \[\frac{p}{q}=\left( \frac{p}{q}\times 100 \right)%\]  




The population of a village is \[4500.{{\left( \frac{11}{18} \right)}^{th}}\] of them are males and the rest are females. If 40 % of the females are married, then the number of married females is:                

(a) 1750                                               

(b) 700                

(c) 750                                                  

(d) 900                

(e) None of these                                


Answer: (b)                                


No. of males\[=\frac{11}{18}\times 4500=2750\]                

No. of females \[=\text{ }4500-2750=1750\]                

Thus no. of married females                

\[=\text{ }40\text{ }%\text{ }\times 1750=700\]  





In a class of 38 girls, 3 are absent, 20 % of the remainder have failed to do the home work. Find the number of girls who did their homework.                

(a) 7                                                      

(b) 25                                            

(c) 28                                                    

(d) 30                                           

(e) None of these                                


Solution: (c)                                

No. of girls present \[=38-3=35\]                

No. of girls who did not do home work \[=20%\times 35=7\]                

No. of girls who did their home work \[=35-7=28.\]  

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