percents problem totally confusing!!

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percents problem totally confusing!!

by eloka » Tue Jun 08, 2010 1:38 am
Dan needs to gain 8% of his current body weight to wrestle in weight class A. Dan needs to lose the same percent of his current weight to wrestle in weight class B. What percent of Dan's class A weight, to the nearest tenth, does he need to lose to get to his class B weight?

so...

this is my formula:

(X/100) = (X1-X1*8%)/(X1+X1*8%)
X/100 = (X1-0.08X1)/(X1+0.08X1)
X/100=0.92X/1.08X
X/100 = 0.92/1.08
X=92/1.08 = 92/(108/100) = 92 * (100/108) = 2300/27

let me know what you think.....HELP..like seriously need your help all the GMAT destroyer
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by liferocks » Tue Jun 08, 2010 1:43 am
Lets dan's body weight is 100x
so class A body weight is 100x+100x*8/100 =108x
class B body weight is 100x-8x=92x

so a class A needs to loose (108-92)x or 16x to perform in class B
this is 16/108 *100% of class A weight 4*100/27 or 400/27 or 14.81%
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by indiantiger » Tue Jun 08, 2010 7:46 pm
Lets say Dan's weight is 100 lbs

Weight for Class A is 100 + 8/100*100 = 108
Weight for Class B is 100 -8/100 *100 = 92

difference between weight of class A and Class B

= 16

16 *100/108 = 0.1481*100 = 14.81 % <I had earlier made stupid mistake here that I corrected>
Last edited by indiantiger on Wed Jun 09, 2010 7:53 pm, edited 1 time in total.
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by liferocks » Tue Jun 08, 2010 7:49 pm
indiantiger wrote:16 *100/108 = 100/8 = 12.5 %
how did u get the bold section?
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by indiantiger » Wed Jun 09, 2010 11:55 am
May be I interpreted the question wrong but this is what I thought

Weight of Class A - Weight of Class B = 108-92 = 16 (thats the gap between Class A and Class B)

% of weight that needs to be lost to get to class B = gap / 108

Let me know if I did something wrong. Would like to get my mistake solved here rather than make it on GMAT :)
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by gmatjedi » Wed Jun 09, 2010 5:51 pm
starting wt 100
increase of 8% to wt class a =108
decrease of 8% to wt class b=92
decrease from wt class a to class b=16/108=14.8%

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by liferocks » Wed Jun 09, 2010 9:07 pm
indiantiger wrote:May be I interpreted the question wrong but this is what I thought

Weight of Class A - Weight of Class B = 108-92 = 16 (thats the gap between Class A and Class B)

% of weight that needs to be lost to get to class B = gap / 108

Let me know if I did something wrong. Would like to get my mistake solved here rather than make it on GMAT :)
what ever u said is the same way I have interpreted.But my question is

% of weight that needs to be lost to get to class B = gap / 108=16/108 =14.81% but in ur calculation it is 100/8=12.5%..which u have corrected Now :).So we are now in same page.
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