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m and r are two numbers on a number line, what is the value [#permalink ]

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27 Sep 2008, 19:57
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This topic is locked. If you want to discuss this question please re-post it in the respective forum. m and r are two numbers on a number line, what is the value of r? (1) The distance between r and 0 is 3 times the distance between m and 0 (2) 12 is halfway between m and r I don't understand the OA. Pls help me out. THx.

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Re: DS - Value of r [#permalink ]

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27 Sep 2008, 21:19

Richardson wrote:

m and r are two numbers on a number line, what is the value of r? (1) The distance between r and 0 is 3 times the distance between m and 0 (2) 12 is halfway between m and r I don't understand the OA. Pls help me out. THx.

1: r and m, both or either, could be -ve or +ve.

for ex: m = 5 and r = 15 hold ro = 3 mo. here r =5

m = -5 and r = 15 also hold the same. r = -5

nsf.

2: if 12 is half way bet r and m, r and m could have any value and either one be on the RHS or LHS. so nsf.

1&2: also nsf.

if m = -12, r = 36, 12 is half ways between r and m and ro = 3 mo.

if m = 6, r = 18, 12 is still halfway between r and m and ro = 3 mo.

so //E//

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Re: DS - Value of r [#permalink ]

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29 Sep 2008, 11:09

hey .. how this come to your mind? " if m = -12, r = 36, 12 is half ways between r and m and ro = 3 mo." I mark C once i guess 6,18 for m & r,but i never thought of -12 and 36

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Re: DS - Value of r [#permalink ]

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29 Sep 2008, 16:48

both are not sufficient together. Since 12 is mid point, r + m = 24 and |r|=3|m| => r = +-m solve for r to get 6 or -12.

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Re: DS - Value of r [#permalink ]

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30 Sep 2008, 04:18

aim2010 wrote:

both are not sufficient together. Since 12 is mid point, r + m = 24 and |r|=3|m| => r = +-m solve for r to get 6 or -12.

Got that I missed -12/36 combination. OA is E>

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Re: DS - Value of r [#permalink ]

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30 Sep 2008, 06:29

Richardson, can u tell me whts the source?

Richardson wrote:

m and r are two numbers on a number line, what is the value of r? (1) The distance between r and 0 is 3 times the distance between m and 0 (2) 12 is halfway between m and r I don't understand the OA. Pls help me out. THx.

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Re: DS - Value of r [#permalink ]

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01 Oct 2008, 06:48

ritula wrote:

Richardson, can u tell me whts the source?

Richardson wrote:

m and r are two numbers on a number line, what is the value of r? (1) The distance between r and 0 is 3 times the distance between m and 0 (2) 12 is halfway between m and r I don't understand the OA. Pls help me out. THx.

It's from GMAPrep (second test).

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Re: DS - Value of r [#permalink ]

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01 Oct 2008, 16:57

I know it is very basic question, but can u tell me how did u solve to get value r=-36?

aim2010 wrote:

both are not sufficient together. Since 12 is mid point, r + m = 24 and |r|=3|m| => r = +-m solve for r to get 6 or -12.

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Re: DS - Value of r [#permalink ]

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01 Oct 2008, 18:55

ritula wrote:

I know it is very basic question, but can u tell me how did u solve to get value r=-36?

aim2010 wrote:

both are not sufficient together. Since 12 is mid point, r + m = 24 and |r|=3|m| => r = +-m solve for r to get 6 or -12.

r + m = 24

|r| = 3|m| => r = 3m or -3m

substitute r = 3m to get m = 6 and r = 18

substitute r = -3m to get m = -12 and r = 36

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Re: DS - Value of r [#permalink ]

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01 Oct 2008, 18:57

i hope it is clear now, let me know if it still does not make sense.

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Re: DS - Value of r [#permalink ]

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01 Oct 2008, 22:38

Richardson wrote:

m and r are two numbers on a number line, what is the value of r? (1) The distance between r and 0 is 3 times the distance between m and 0 (2) 12 is halfway between m and r I don't understand the OA. Pls help me out. THx.

IMO E

1)|r|=3|m|

with al the values of m , val of r changes INSUFFI

2) r-m=12 or m-r =12 => with diff m can change !!!

COMBINING BOTH

say r =3m then m=6 ,r=6or m= -6,r=-18 hence INSUFFI

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Re: DS - Value of r [#permalink ]

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02 Oct 2008, 07:56

Oh yes. dats so simple. Silly me. I ignored negative value

aim2010 wrote:

i hope it is clear now, let me know if it still does not make sense.

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Re: DS - Value of r
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02 Oct 2008, 07:56