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# Maths

### Problems on Train

Time taken to cross a Platform - Length of (Train + platform) to Speed of Train Time taken to cross a Bridge – Length of (Train + platform) to Speed of Train When two trains move towards each other, then the time taken to cross each other is - Ratio of Sum of Lengths of both Trains to the Sum of their Speeds

### Theory: Time and Distance

Speed is a very basic concept in motion which is all about how fast or slow any object moves. Tips and Tricks to Solve "Time and Distance" Aptitude Problems with Important Formulas, Shortcuts, Core Concept

### Important Notes on Simple Interest

Principal – The money which is borrowed or lent for a certain period of time is called Principal or the Sum. Interest – The extra money which is paid along with the principal. Amount = Principal + Interest

### Time and Work Notes

Time and Work Theory Notes -If M1 men can do a W1 piece of work, working T1 hours daily in D1 days and M2 men can complete W2 work, working T2 hours in D2 days then – M1 D1 T1 W2 = M2 D2 T2 W1

### Short Notes on Pipes and Cisterns

If a Pipe A alone empties a tank in x hours and another Pipe B alone empty it in y hours. Then the time taken to empty the tank when both pipes are open = (x × y/x + y) hours.

### Notes on Ratio and Proportion

Ratio and Proportion What do you mean by Ratio? In a ratio of a:b, 'a' is called the first term or antecedent, and 'b' is called the second term or consequent. What do you mean by Proportion? i.e., a × d = b × c Important Results

### Important Notes on Percentage

Percent is derived from Latin word 'per centum' which means 'per hundred. Percentage is a way of comparing quantities. Percentages are basically numerators of fractions with denominator 100. Percent is represented by the symbol - '%'. Ex- 1% means 1 out of 100 or one hundredth. 1% = 1/100 = 0.001 Interpreting Percentages Ex- What do you mean by this statement. let say - "Raj saves 25% of his income. Interpretation - It means 25 parts out of 100, or it means Raj is saving 25 rupees out of every 100 rupees that he earns. Important Formulae % Change - (Increase or decrease) ℅change = (final value - Initial Value)*100/Initial Value