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backsolving

by resilient » Sun Jun 08, 2008 5:58 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?

40
100
120
140
180

I bacsolved with this and didnt get very far.

Can you show me a way.
qa is b
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by VP_Jim » Sun Jun 08, 2008 6:18 pm
I think backsolving is a good way to do this. Note that you can skip answer choice A because that would mean Brian has negative dollars!

Let's look at B, then. I would usually choose to start with C, but since $100 is easy to work with, I did that first.

If Jennifer has $100, Brian then has $40. If Jennifer gives up 1/5 of her money ($20), she'll have $80 and Brian will have $60.

Since Brian now has 25% less than Jennifer now has, B is the right answer.
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by netigen » Sun Jun 08, 2008 6:34 pm
Just create two eqs

J = 60 + B

(4J/5) x (3/4) = B + J/5

solve to get J = 100
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hmm

by resilient » Sun Jun 08, 2008 7:49 pm
in retrospect, I dont know why this question was so hard for me during the cat exam. Seems so easy.
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by netigen » Sun Jun 08, 2008 8:38 pm
tension gets to you when the clock is ticking :) happens to most of us.
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very true

by resilient » Mon Jun 09, 2008 8:13 am
yes the tension gets me an clouds my thinking. The question is very straightforward and not too challenging once you backsolve. Lesson learned..stay cool.
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