Math questions from any Manhattan Prep GMAT Computer Adaptive Test.
FrancescaI776
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Jennifer has 60 dollars more than brian

by FrancescaI776 Tue Jun 16, 2015 1:20 pm

Jennifer has 60 dollars more than Brian. If she were to give Brian 1/5 of her money, Brian would have 25% less than the amount that Jennifer would then have. How much money does Jennifer have?

A. 40

B. 100

C. 120

D. 140

E. 180

Can this problem be solved with smart numbers instead of algebra?

Thanks
RonPurewal
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Re: Jennifer has 60 dollars more than brian

by RonPurewal Wed Jun 17, 2015 7:28 am

smart numbers, no.
in this problem, there are correct numbers for the quantities. i.e., there are specific dollar values thot jennifer and brian have, for the 'before' and 'after' situations.

'smart numbers' means that you make up your own values. you can't do that here, because, if you make up values, they'll be wrong (unless you are so incredibly lucky as to choose the correct values at random).
RonPurewal
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Re: Jennifer has 60 dollars more than brian

by RonPurewal Wed Jun 17, 2015 7:31 am

perhaps you're just using the wrong name, and are actually asking about BACKSOLVING?

if so, then, yes, backsolving will definitely work.
* start with an answer choice. this is how much jennifer has (to begin with).
* subtract 60; that's how much brian has.
* now, figure 1/5 of jennifer's money, and give it to brian. (don't forget to take it away from jennifer, too!)
* how much does brian have now? what value is %25 less than jennifer has now? if both of these are the same, you win. if not, throw in another number and do the same steps.
FrancescaI776
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Re: Jennifer has 60 dollars more than brian

by FrancescaI776 Wed Jun 17, 2015 11:19 am

Great. I needed to figure out how to solve the problem with numbers instead of algebra. Backsolving works perfect. Thank you
RonPurewal
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Re: Jennifer has 60 dollars more than brian

by RonPurewal Thu Jun 18, 2015 2:07 pm

no problem.