the answer could be between 30 and 40 and we need to round off...so even decimal point numbers make difference here....even to guess...
so we need to calcuate so hope it is no good for 2 minutes solving ...that also at the end of the set ....unwise
thanks

Can anyone suggest a simple method to solve this problem.

I believe there is a mistake in wording the question. It needs to be stated that x represents the weight of each box, and that each subsequent box weights x-x%, and perhaps even give example:

If box weighs 29kg, then the next box will weigh 29kg - 29%. With this, it is easier to comprehend. From the original stem, i concluded that each subsequent box weighs 10% less than the previous one, hence, 10, 9, 8,1, 7.29, and finally 6.561... (if my calculations are correct).
Bottom line, we need to make sure that x changes with the weight of each box, and is not at constant 10%.

hey guys,
I havent done a CAT exam yet, is this really a 750 level question?

is there any way to reduce the time spent on the calculations ? any technique for faster or more elegant calculation ?

"x - x%" makes no sense, you cannot substract percents from kilograms. This formula taken aside, the tests are really helpful , thanks guys!

I saw this question in the new GMAT club test, which doesn't have % signal, making the question very akward:
5 boxes are placed in a stack by weight from lightest to heaviest. The heaviest box weighs x kg and then next heaviest weighs x less than the heaviest box and the next heaviest box weighs x−x less than the next heaviest, and so on. If the heaviest box weighs 10kg, approximately what percent less weight is the lightest box than the heaviest one?
Please correct the question poll, Admin.

Same question without % sign appeared in a test ( D01-45) for me as well.

Please correct it.

Is there a formula-based method for something like this? I solved it by calculating each weight individually, but wouldn't want to get stuck with an exam question that asks for weight of 10th box, or 30th box. Or would be beyond the scope of the GMAT?

This question was removed from the tests. So, I wouldn't worry about it at all.
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