PERCENTAGE

PERCENTAGE

Percent :-The meaning of the term percent is ‘for every hundred’.
It can be defined as follows:
“A percent is a fraction whose denominator is 100 and the numerator of the fraction is called the rate percent.” percent is denoted by the sing %.
Some Formula to solve question.

• Formula 1 If we have to find y% of x, then
  y% of x = x × y/100
• Formula 2
  Expressing percent (x%) into fraction.
  Required fraction = x/100
• Formula 3
  Expressing a fraction = ( x/y) percent
  Required percentage =( x/y ×100)%
• formula 4
  To find how much percent one quantity is of another.
  Required percentage = (The quantity to be expressed in percent)/(2nd quantity (in respect of which the percent has to be obtained))×100
  Mind it? For this formula, both quantities must be in same unit.
• formula 5
  (i) If x is a% more than y, then y is less than x by
  (a/(100+a)×100) %

(ii)If x is a% less than y, then y is more than x by
(a/(100¬-a)×100) %

• Formula 6
  It the valueof number is 1st increased by a% and later decreased by a%, then the net effect is always a decrease
  which is equal to a2% and a and is written as
  a^2/(100 )% or (a/10)^2%
• Formula 7
  When the value of object is first changed (increased or decreased) by a% and then changed (increased or decreased) by b%, then
  Net Effect = [±a±b+(±a)(±b)/100]%
  Net effect is increased or decreased according to the +ve and -ve sign, respectively.
• Formula 8
  If the population of a town is P and it increases (or decreases) at the rate of R% per annum, then
  (i) Population, after n year = P (1±R/100)^n
  (ii)Population, n year ago = P/(1±R/100)^n
  Mind it? Use ‘+’ sign for increment and ‘-’ sign for decrement.