There are total 30 students in the piano class.
When a number can be divided by another number then they can be written as p : q , when two ratios can be equated using an equal sign then they are said to be in proportion.
It is given that the total number of girls is 40% of the total students
The ratio of total students to girls is 100 :40
= 10 :4
= 5 : 2
It is also given that in the total number of students 12 were girls
Let total students be x
Then the ratio is x : 12
As both the ratio are same and so can be equated and the proportion will be
5 : 2 = x : 12
5/2 = x /12
x = 30
Therefore there are total 30 students in the piano class.
To know more about Ratio and Proportion
https://brainly.com/question/26974513
#SPJ1
