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# Important Formula & Tips: Percentages Quant Notes | EduRev

## Quant : Important Formula & Tips: Percentages Quant Notes | EduRev

The document Important Formula & Tips: Percentages Quant Notes | EduRev is a part of the Quant Course Quantitative Aptitude (Quant).
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• In mathematics, a percentage is a number or ratio that can be expressed as a fraction of 100. If we have to calculate percent of a number, divide the number by whole and multiply by 100. Hence, the percentage means, a part per hundred. The word percent means per 100. It represented by the symbol “%”.
• Percentages have no dimension. Hence it is called a dimensionless number.
• Percentages can also be represented in decimal or fraction form, such as 0.6%, 0.25%, etc.

Important Formulas

1. Percent implies “for every hundred” - % is read as a percentage and x % is read as x per cent.
2. To calculate:
• p % of y = (p/100) * y = (p * y)/100
• p % of y = y % of p
3. To find what percentage of x is y: y/x * 100
4. To calculate percentage change in value
• Percentage change = {change/(initial value)} x 100
5. Percentage point change = Difference of two percentage figures
6. Increase N by S % = N( 1+ S/100 )
7. Decrease N by S % = N (1 – S/100)
8. If the value of an item goes up/down by x%, the percentage reduction/increment to be now made to bring it back to the original point is 100x/ (100 + x) %.
9. If A is x% more /less than B, then B is 100x/(100 + x) % less/more than A.
10. If the price of an item goes up/down by x %, then the quantity consumed should be reduced by 100x/ (100 + x)% so that the total expenditure remains the same.
11. Successive Percentage Change
• If there are successive percentage increases of a % and b%, the effective percentage increase is: {(a + b + (ab/100)}%

12. Percentage – Ratio Equivalence

Table: Fractions and their percentage equivalents:

Percentage Tips

• r% change can be nullified by (100r/100 + r)% change in another direction.
Example: An increase of 25% in prices can be nullified by a reduction of [100 x 25/(100 + 25)] = 20% reduction in consumption.
• If a number ‘x’ is successively changed by a%, b%, c%...
⇒ Final value =
• The net change after two successive changes of a% and b% is:

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## Quantitative Aptitude (Quant)

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