In this post I describe some of the tricks of percentage calculation .

by a certain

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ans . suppose B's salary is 100 then A's salary is 80

4. A number is increased by 12% and again deceased by 18% then how much change in that value.

by a certain

**percent , we**means that many hundredths thus , x percent means x hundredths**written**as x%

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**Fraction value of percentage :**

1/2 = 50 % 1/3 = 33.33% 1/4 = 25% 1/5 = 20 %

1/6 =16.67% 1/7 = 14.28% 1/8 =12.5% 1/9 = 11.11

**Note :**these fraction value helps to minimize the calculation

#### Formula:

- if the price of a commodity increases by R% , then the reduction in consumption so as not to increase the expenditure is
**100*R/(100+R)%.** - if the price of a commodity decreases by R% , then the increases n consumption so as not to decreases the expenditure is
**100*R/(100-R)%.** - value of machine after n years = p(1-R/100)power n .
- if A is R% more than B , then b is less than A by
**100*R/(100+R)%.** **if A is R% less than B , then b is more than A by****100*R/(100-R)%.**

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**Example:**

**1. if**1/5 of a number is 25 less then 1/4 of a same number . what will be 3/2 of number .

ans.

as you know 1/5 = 20% and 1/4 = 25%

so difference b/w these two is 5% which is equal to 25

then 5% *20 ---- 25*20 100% ----500

and 100% percent is the real value

you can now calculate 3/2 so ans is

you can now calculate 3/2 so ans is

**750**

**2.**if the numerator of fraction is increase by 20% and denominator is decrease by 80% then fraction becomes 18/15. what is the actual fraction .

ans . 120% N/20% D = 18/15

then N/D = (18/15 )*20/120

N/D = 1/5 answer

3 . if A's salary 20% less then B's salary then B's salary is how much more then A.

ans . suppose B's salary is 100 then A's salary is 80

now you can calculate b's salary in respect to A

( 20/80)* 100 = 25% is answer

#### formula for this problem % change = (x)+(y)+x*y/100

Note take the value with symbol , if increase then take '"plus" if decease in value then take "minus". this formula is applicable for circle , square , triangle etc

12- 18 - 216/100 = -8.16 decrease is value by 8.16%

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