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 Post subject: PS exponent questionPosted: Tue Aug 31, 2010 12:45 am

Joined: Thu Jul 08, 2010 11:09 pm
Posts: 33
(58^2 + 58^2 ) / (29^2)

a) 4
b) 8
c) 29
d) 58
e) 116

I understand that by factoring things cancel out, but I made the numbers more friendly by doing this:
(60^2 + 60^2 ) / (30^2)

and I got 8 but i dont understand how I could get the same answer. Shouldnt I have increased the denom by 2 and made it 31?

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 Post subject: Re: PS exponent questionPosted: Tue Aug 31, 2010 5:37 pm

Joined: Thu Jul 03, 2008 2:13 pm
Posts: 117
Hey TJ,

Nice work - especially when the answer choices are that far apart you can often get away with an estimate, which is what you did.

It was more coincidental that you got the exact same number than anything else. With division, adding the same number to the numerator and denominator doesn't necessarily keep them in proportion:

4/2 = 2
(4+2)/(2+2) = 6/4 = 1.5

The only way to keep the proportion the same is to multiply top and bottom by the same thing.

By rounding off 58 to 60 and 29 to 30, you were able to take a quick estimate, which was certainly viable, but by doing that you weren't likely to get the same exact number...that was just coincidental.

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