Percentage is a fraction whose denominator is always 100. x percentage is represented by x%.
To express x% as a fraction :
x% = x/100Thus 10% = 10/100 (means 10 parts out of 100 parts)
= 1/10 (means 1 part out of 10 parts)
To express x/y as a percentage :
We know that x/y = (x/y× 100 )Thus 1/4 = ( 1/4 ×100 )% = 25%
and 0.8 = ( 8/10 ×100 )% = 80%
If the price of a commodity increases by R%, then reduction in consumption as not to increase the expenditure is-
[ R/(100+R)×100 ] %If the price of a commodity decreases by R%, then the increase in consumption as not to decrease the expenditure is -
[ R/(100-R)×100 ] %Result on Population :
Let the population of a town be P now and suppose increases the rate of R% per annum, then :
1. Value of the machine after n Years
- Population after n years = P ( 1+ R/100 )n
- Population n years ago = P /( 1+ R/100 )n
Result on Depreciation :
Let the present value of a machine be P. Suppose depreciates at the rate of R% per annum Then :1. Value of the machine after n Years
= P ( 1- R/100 )n
2. Value of the machine n years ago
= P /( 1- R/100 )n
- If A is R% more than B, then B is less than A by
If A is R% less than B, then B is more than A by
[ R/(100-R)×100 ]%
- Net % change = x + y + xy/100
Some Observation
#1
If 20% candidate failed in an exam then observations are- 80% represent passed in exam
- 100% represent total appeared in exam
- (80%-20%) = 60% represent difference between passed and failed candidate in exam
#2
If a number is increased by 25% then observations are
- 100% represent the old number
- 125% represent the new number.
#3
Remember that Base in the given sentence (Question) is always 100%
Eg. Income of Ram is increased by 20%
In this sentence
100% - represent the income of Ram
20% - represent increment
120% - represent new income of Ram.
Remember it :
1/3 = 33 1/3%
1/6 = 162/3%
1/7 = 142/7%
1/8 = 121/2%
1/9 = 111/3%
1/10 = 10%
1/11 = 91/11%
1/10 = 81/3%
1/13% = 79/13%
6.25% = 1/16
125% = 5/4
150% = 3/2
350% = 7/2
Examples
#1
Q. If the difference between 62% of a number and 3/5th of that number is 36. what is the number ?
Let the number be x.
Then x × 62% - x × 3/5 = 36
x ×62% -x V 60% = 36 (60% = 3/5)
x ×2% = 36
x ×2/100 =36
x = 36 ×100/2 = 1800
Q. 40% of Ram's income Rs. 1200 Then Find
- 75% of Ram's income ?
- 1/4 part of Ram's income ?
- 1/3 part of Ram's income ?
40% = 1200 Rs.
75% = 1200/40 ×75 = 2250 Rs.
Trick : 1200 / 40 × 75 = Rs. 2250/-
40% of income = Rs. 1200
Then 1/4 part (i.e. 25% ) of Ram's
income = 1200/40 ×25
= Rs. 750/- Ans
40% of Ram's income
= Rs. 1200
i.e. 2/5 part of Ram's income
= Rs. 1200
Then total income of Ram
= Rs. 1200 ×5/2
1/3 part of Ram's income
= Rs. 1200 × 5/2 × 1/3
= Rs. 1000 Ans.
1200/2/5 × 1/3
= 1200/2 × 5/3 = 1000
This entry passed through the Full-Text RSS service - if this is your content and you're reading it on someone else's site, please read the FAQ at http://ift.tt/jcXqJW.
No comments:
Post a Comment