Posted: Wed Jan 24, 2007 12:10 pm Post subject: Percentage
1)The volume of a sphere A is 70^10/27% less than that of B.If the area of B is x% greater than that of A,x is equal to
1)(1900)^2/3/9
2)125
3)225
4)None of these
2)On St.Vincent's birthday,chocolates were distributed to the children of the primary classes.If the total Strenght of the primary classes increase by 12% this year compared to that of the last year and the total number of chocolates distributed increases by 34.4%,the number of chocolates given to each child increases by what percent?
1)22.4%
2)24.1%
3)18%
4)20%
Posted: Thu Apr 12, 2007 5:55 pm Post subject: solution to percentage problems
Hi,
1.) answer = 125
as since volume of A is less than that of B by 70^10/27% ,so take the ration of Va/Vb ,which comes out to be 8/27 which is nothing but ratio of cubes of the radii of A and B
so , Ra/Rb =2/3
Also from statement about areas, take the ratio of areas of A and B ,which comes out to be Aa/Ab= 1/(1+x/100 )-------------a)
which is also equal to the ratio of squares of the radii of A and B ,i.e, 4/9
equate a) with 4/9 ,we get x as 125..........
2.) assume no. of chocolates and no. of children in the previous year as 100 each
so currently no of chocolates = 134.4 ( increase by 34.4 %)
no. of children = 112 (12 % increase )
previously chocolate per child = 1
now ,chocolate per child = 134.4/112
take the percentage diffrence w.r.t 1
so, answer is ((134.4/112) - 1)/1 ^ 100
which is nothing but 20%
