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Manager
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If R and S are Integers, is R +S divisible by 3? 1) S is [#permalink]
 13 Oct 2007, 18:19
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If R and S are Integers, is R +S divisible by 3?
1) S is divisible by 3
2) R is Divisible by 3
Please explain...I am suspecting that the OA from the OG is wrong...just want to see what people thinks...will post OA tomorrow....thanks
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VP
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R+S/3 = integer ?
statement 1
S is divisible by 3
S can be 3 while R can be 7 or 3
insufficient.
statement 2
R is divisible by 3
R can be 3 while R can be 7 or 3
insufficient
both statements
since R and S are both divisible by 3 then the sum of them is divisible by 3.
lets say R=6 S=12
6+12/3 = 3(2+4)/3 = 6
the answer is (C)
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Manager
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Yes, the OA is C...
When I was doing this question, i was about to pick C, then something occured to me...
the question did not say anything about R or S being Positive or negative integers....
let's say if R=3 and S= -3, then the resuld would be ZERO....which is not divisible by 3 anymore....
can someone tell me if my reasoning is correct...if I am correct, then the answer should be E instead of C....
Please let me know what you guys think, thanks....
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Director
Joined: 22 Aug 2007
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garyxb wrote: Yes, the OA is C...
When I was doing this question, i was about to pick C, then something occured to me...
the question did not say anything about R or S being Positive or negative integers....
let's say if R=3 and S= -3, then the resuld would be ZERO....which is not divisible by 3 anymore....
can someone tell me if my reasoning is correct...if I am correct, then the answer should be E instead of C....
Please let me know what you guys think, thanks....
ANY NUMBER is divisor of zero.
0/5=0
0/(3/2)=0..........................
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Manager
Joined: 24 Jul 2007
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IrinaOK wrote: garyxb wrote: Yes, the OA is C...
When I was doing this question, i was about to pick C, then something occured to me...
the question did not say anything about R or S being Positive or negative integers....
let's say if R=3 and S= -3, then the resuld would be ZERO....which is not divisible by 3 anymore....
can someone tell me if my reasoning is correct...if I am correct, then the answer should be E instead of C....
Please let me know what you guys think, thanks.... ANY NUMBER is divisor of zero. 0/5=0 0/(3/2)=0.......................... ok,
so going back to our question, if R=3 and S= -3, the result is 0, and 0 is also divisible by 3, so the answer is still C.
Can someone confirm that this is the case?
thanks
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Director
Joined: 22 Aug 2007
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garyxb wrote: IrinaOK wrote: garyxb wrote: Yes, the OA is C...
When I was doing this question, i was about to pick C, then something occured to me...
the question did not say anything about R or S being Positive or negative integers....
let's say if R=3 and S= -3, then the resuld would be ZERO....which is not divisible by 3 anymore....
can someone tell me if my reasoning is correct...if I am correct, then the answer should be E instead of C....
Please let me know what you guys think, thanks.... ANY NUMBER is divisor of zero. 0/5=0 0/(3/2)=0.......................... ok, so going back to our question, if R=3 and S= -3, the result is 0, and 0 is also divisible by 3, so the answer is still C. Can someone confirm that this is the case? thanks Since the question comes from my above post, let me answer it too.
The question asks (R+S)/3= INTENGER ?
if R+S =0------------> 0/3=0 and zero is also an intenger.
Considering both statements the asnwer is always YES, so C it is
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Director
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easy C
just think quickly
3 + 3 yes divis by 6
but 3 + 7 obviously not
so either insufficient
put them together
you can factor out a 3 from R & S, then factor it out, so their sum is equal to 3 as well
ie
R+S = 3*X + 3*Y = 3*(X+Y)
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VP
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CONFIMRATION
u can divide 0 by any number other than 0
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Manager
Joined: 24 Jul 2007
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IrinaOK wrote: garyxb wrote: IrinaOK wrote: garyxb wrote: Yes, the OA is C...
When I was doing this question, i was about to pick C, then something occured to me...
the question did not say anything about R or S being Positive or negative integers....
let's say if R=3 and S= -3, then the resuld would be ZERO....which is not divisible by 3 anymore....
can someone tell me if my reasoning is correct...if I am correct, then the answer should be E instead of C....
Please let me know what you guys think, thanks.... ANY NUMBER is divisor of zero. 0/5=0 0/(3/2)=0.......................... ok, so going back to our question, if R=3 and S= -3, the result is 0, and 0 is also divisible by 3, so the answer is still C. Can someone confirm that this is the case? thanks Since the question comes from my above post, let me answer it too. The question asks (R+S)/3= INTENGER ? if R+S =0------------> 0/3=0 and zero is also an intenger. Considering both statements the asnwer is always YES, so C it is Thanks everyone, I finally got that through my thick head.....so yes, the OA is C...appreciate the help.... 
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