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hundreth digit

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naveenhv
 Post subject: hundreth digit
 Post Posted: Mon Apr 25, 2011 12:45 pm 
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What is the hundredths digit of the decimal z?

1) The tenths digit of 100z is 2

2) The units digit of 1000z is 2
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smohit04
 Post subject: Re: hundreth digit
 Post Posted: Mon Apr 25, 2011 11:40 pm 
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Posts: 28
E.

from both the options we can determine that the decimal z is of type x.xx2 but we could not determine the hundredths place from either/both options.
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RonPurewal
 Post subject: Re: hundreth digit
 Post Posted: Wed Apr 27, 2011 5:01 am 
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Posts: 7146
Quote:
(1) The tenths digit of 100z is 2

this means that you can write
100z = ......xxxxxxxx.2xxxxxxxx..... (where the letters are digits)
so, dividing by 100 gives
z = ....xxxxxx.xx2xxxxxxxx... (because division by 100 moves the decimal 2 spots over)
the hundredths digit here is still an unknown mystery digit -- we only know that 2 is the thousandths digit of z -- so, insufficient.

Quote:
(2) The units digit of 1000z is 2


this means that you can write
1000z = ......xxxxxxxx2.xxxxxxxx..... (where the letters are digits)
so, dividing by 1000 gives
z = ....xxxxxx.xx2xxxxxxxx... (because division by 1000 moves the decimal 3 spots over)
again, the hundredths digit here is still an unknown mystery digit -- we only know that 2 is the thousandths digit of z -- so, insufficient.

together:
we still have the same information given by either statement alone, and nothing new.
still insufficient.

(e)
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naveenhv
 Post subject: Re: hundreth digit
 Post Posted: Fri May 06, 2011 1:57 pm 
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Thanks a ton Ron. Thats an excellent approach for this problem. Makes it so easy to digest.
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jnelson0612
 Post subject: Re: hundreth digit
 Post Posted: Sat May 07, 2011 4:17 pm 
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Great. :-)

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Jamie Nelson
ManhattanGMAT Instructor
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