Ratio and proportion: A very important chapter in whole quantitative aptitude. In this chapter, we learn how to solve problems based on ratios with out using formula but with only logic. Ratio is nothing but simplified comparison of any two numbers or quantities or anything. If two ratios are equal we will say they are in proportion. We will learn a small and simple logic which involves total parts and so on. It is high by less or less by high concept.
For suppose take that I had gone to a tiffin center. And there the cost of 1 dosa is Rs 15. I had eaten 2 dosa. What bill I had to pay now?
We all know it's Rs 30/-. But what's the logic behind it?
Cost of 1 dosa = Rs 15/-
Cost of 2 dosa = ?
Now put a question in the place of question mark. We will get high as the answer. So high by less Rs 15 will give us Rs 30/- as the answer. Same as reverse also. If the answer is less. Less by high * number that is upside of the question mark.