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Alexander
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If Mary has half as many cents as Nora...

by Alexander Wed Apr 08, 2015 6:17 pm

Hi -

This is from 5lb book of GRE questions p483 #29.

I don't understand the explanation on page 502 and how Mary would have 5 cents.

The smart numbers I used are:

Mary = $1 = 100 cents
Nora = $2 = 200 cents

Those numbers fit the restrictions.... So 200-100/100 = 1 * 100 = 100%

What am I missing?

Thanks,
Alexander
tommywallach
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Re: If Mary has half as many cents as Nora...

by tommywallach Thu Apr 09, 2015 10:31 pm

Hey Alexander,

You misread the question. Mary has half as many cents as Nora has DOLLARS. You did it as Mary has half as many cents as Nora has (cents). See?

-t
n00bpron00bpron00b
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Re: If Mary has half as many cents as Nora...

by n00bpron00bpron00b Fri Apr 10, 2015 5:41 am

Hi Tommy,

I have a similar doubt -

How can we solve an equation where the LHS and RHS have different units without converting them to the same level
Mary - cents = (Nora - dollars / 2)

If Nora has $100

Mary - cents = ($100/2)

Mary - cents = $50 - I don't think this equation makes any sense

Thanks,
noob
tommywallach
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Posts: 1917
Joined: Thu Mar 31, 2011 11:18 am
 

Re: If Mary has half as many cents as Nora...

by tommywallach Sat Apr 18, 2015 12:50 am

Not seeing the confusion.

Mary has half as many cents as Nora has DOLLARS.

So if Nora has 2 dollars, Mary has 1 cent.
If Nora has 10 dollars, Mary has 5 cents.

If you want to equation it, just notice what's happening. We go from 2 dollars (200 cents) to 1 cent. We go from 10 dollars (1000 cents) to 5 cents. Mary always has 1/200th the money that Nora has.

Does that make sense?

-t