Introduction to percentages :
A percent means per hundred,percentage is a way of expressing a number as a fraction of 100. The symbol used for percent is , "%",
Percentage is a relative term ,it is used to express how large/small one quantity is, relative to another quantity. For example, 60% is equal to `60/100` , or 0.60.
The percent symbole equalent to `1/100` = 0.01 , for example 35% of 300 can be written as (`35/100` ) × 300 = 105.
Formula to calculate percentage
Simple rules to find percentage of numbers
To calculate a percentage of a percentage, make the percentages to fractions and multiply .
The easy way to calculate Addition in percentage (discount `x1` % + `x2` %):
y = `((x_1+x_2)-(x_1 xx x_2))/100`
if the percentage is given and asked to find what is the amount that contirbutes of the total amount
then Value = `("Percent value") / (100) xx "Total value"`
It is very important to know what is the total value that corresponding to 100% to do problems on percentage
Ex 1 : What is 20% of 30?
Sol:Step 1Here the Total value is 30 and the percentage is 20%
Use the above mentioned formula to find the value corresponds to 20% i.e
Step 2:Value = `("Percent value") / (100) xx 100 `
Step 3:Value = `(20)/(100) xx 30` = `6`
so the 20% of the 30 is 6.
Ex: 2 There are 60 students in the class , and 24 of them are girls. What is the percentage of girls in the class?
Sol:Step 1: Here the total number of students in a class is 60 out of which 24 are girls
Stpe 2:To calculate percentage of girls in class use the formula
Percentage (%) = `("Given value") / ("Total value") xx 100`
Step 3:Percentage(%) of girls = `(24)/(60) xx 100` = `40`
The percentage of girls present in the class is 40% .
Some points on percent changes:
100% of initial + 100% of increase = 200% of initial , which means the quantity has doubled.