Thursday, October 25, 2007



1. If x% is deducted on tax and y% of the remaining is spent on education and still there is    a balance, the formula is :-

Balance * [ 100/(100-x) ] * [ 100/(100-y) ] * [ 100/(100-z) ]

2. The population of a town is 'P'. It increased by x% during Ist year, increased by y%    during IIst and again increased by z% during Ist. The population after 3 years will be,

P * [ (100+x)/100 ] * [ (100+y)/y ] * [ (100+z)/100 ]

3.                                              % of effect  
(i) Inc of x% Dec of x% x-y-[(x*y)/100]
(ii) Inc of x% Inc of y% (x+y)+[(x*y)/100]
(iii) Dec of x% Inc of y% [-x2/100]
(iv) Dec of x% Dec of y% (-x-y)+[(x*y)/100]
(v) Inc of x% Dec of x% [-x2/100]
(vi) Inc of x% Inc of x% 2*x+[x2/100]

4. (i) If the sides of the traingle,rectangle,square,circle,rhombus etc is increased by x%.Its        area is increased by


   (ii)If decreased x%.Its ares is decreased by,


5. In an examination x% failed in Hindi and y% failed in Science, if z% of the candidates    failed in both of the subjects. The percentage of students who passed in both of the    subjects is,


6. If A's income is r% more than B's income, the B's income is less than A's income by

(r/100+r) * 100%

7.If A's income is r% less than B's income, then B's income is more than A's income by

(r/100-r) * 100

8. (i)If the price of comodity increases by r% then reduction in consumption so as not to       increase the expenditure is

(r/100+r) * 100

   (ii)If the price of comodity decreases by r% then,


9.If the population of town (or) length of a tree is 'p' and its annual increase is r% then,

    (i)populaton (or) length of a tree after 'n' years is,


   (ii)population (or) length of a tree 'n' years ago is,


10.If the population of town (or) value of a machine is 'p' and annual decrease is r% then,
    (i)populaton (or) value of machine after 'n' years is,


   (ii)population (or) value of a machine 'n' years ago is,


11.If 'A' is x% of 'C' and 'B' is y% of 'C' then 'A' is

(x/y) * 100%

   of 'B'.

12. If two values are respectively x% and y% more than a third value, then the first is

[(100+x) / (100+y)] * 100%

   of second

13.Total no.of votes  =

(Difference in votes/Difference in %) * 100

14.Maximum marks  =

[(pass marks/pass %) * 100]

15.Total marks  =

(Difference in marks / Difference in %)*100

16. (i)Reduced rate  =

[(Amount/Quantity more) * (Reduction % /100)]

     (ii)Original rate (or) previous rate  =

[(Amount/Quantity more) * (Reduction % /100-reduction%)]

17. (i)Increased rate  =

[(Amount/Quantity less) * (increase % /100)]

     (ii)Original rate (or) previous rate  =

[(Amount/Quantity less) * (Increase % /100-increase%)]

18. If the numeratorof fraction is increased by x% and its denominator is diminished by       y% ,the value of the fraction is A/B.Then the original fraction is,

(A/B) * [(100-y) / (100+x)]

1 comment:

Born_to_fly ( Ruchi ) said...

Very Useful, Thanks a Ton ^_^