What is Ratio

Consider this example. In a mixture of 35 liters of milk and water, the milk has four parts and water has part. Obviously there are a total of 5 parts; hence one part is equal to 7 liters. The quantity of milk being 4 parts i.e. is 28 liter and that of water is one part, i.e. 7 liter. We shall say that the ratio of milk and water in this solution is 4 and 1. This shall be written as 4:1. Mathematically, this is 4/1.

Hence, A:B, i.e. A/B is a ratio between two quantities of same unit. The first element of ratio is called antecedent and second one is called consequent.

Obviously, the order of the two quantities is important, i.e. A:B ≠B:A. It means that the ratio of milk and water in solution is not equal to that of water and milk. The former is 4:1, later is 1:4. Of course, we all know that 4/1 is not equal to 1/4.

Now keeping this ratio fixed, if the quantity of milk is increased by 12 liter and it becomes 40 liter, the quantity of water will have to be increased 3 liter so that the quantity of water becomes 10 liter, and the ratio of milk and water remains the same, i.e. 40:10 or 4:1.