|Class 6 Maths Ratio And Proportion||Introduction|
It is common to compare two quantities which are of same type. We compare prices of two things, height to of two people, size of different things, age of people etc. For e.g. Let the price of a notebook is Rs. 10 and the price of a diary is Rs.30. One way of comparing these prices is to calculate the difference we them. Hence, we get that the price of a diary is Rs.20 (Rs30 – Rs10) more than the price of a notebook. But if we wish to compare the prices of these two things then taking the difference is not enough to express the comparison.
Thus, we use ratio. In many situations, calculating the ratio is considered as a more meaningful way of comparing quantities. It is obtained by using division, i.e. by seeing how many times one quantity is to the other quantity. This method is known as comparison by ratio.
For example, the price of a notebook is Rs.10 and price of a diary is Rs.30.
We say that price of a diary and price of a notebook are in the ratio 3: 1. This is obtained by:
Price of a Diary/ Price of a Notebook = 30/10 = 3/1
We can say that the cost of the diary is three times the cost of the notebook.