Remainder
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we can rewrite the given info as following:
n=3x+2 and t=5y+3
to find the remainder when nt is divided by 15:
statement (1): n-2 is divisible by 5
3x+2-2=3x is divisible by 5, which means x is divisible by 5. so, 3x is divisible by 15, with the remainder "0".
when divided by 15, nt will have a remainder "0".
SUFFICIENT
Statement (2): t is divisible by 3
5y+3 is divisible by 3....5y is divisible by 3, which means 5y+3 is divisible by 15 with the remainder 3.
Since n is divided by 3 with the remainder 2, when multiplied by t, it doesn't give precise answer, so insufficient.
So, the OA is A
correct?
n=3x+2 and t=5y+3
to find the remainder when nt is divided by 15:
statement (1): n-2 is divisible by 5
3x+2-2=3x is divisible by 5, which means x is divisible by 5. so, 3x is divisible by 15, with the remainder "0".
when divided by 15, nt will have a remainder "0".
SUFFICIENT
Statement (2): t is divisible by 3
5y+3 is divisible by 3....5y is divisible by 3, which means 5y+3 is divisible by 15 with the remainder 3.
Since n is divided by 3 with the remainder 2, when multiplied by t, it doesn't give precise answer, so insufficient.
So, the OA is A
correct?
- logitech
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n=3a+2
t=5b+3
St 1) n-2 = 5x ; we know that n-2 =3a so n-2=15t and n = 15t+2
no information on t - insuf
St 2) t=5b+3 ; t=3y ..5b+3 = 3y ...5b=3(y-1) and t = 15m + 3
no info on n - insuf
ST 1+2)
(15t+2) (15m+3) / 15
Remainder: 2x3 = 6
Hence, C
t=5b+3
St 1) n-2 = 5x ; we know that n-2 =3a so n-2=15t and n = 15t+2
no information on t - insuf
St 2) t=5b+3 ; t=3y ..5b+3 = 3y ...5b=3(y-1) and t = 15m + 3
no info on n - insuf
ST 1+2)
(15t+2) (15m+3) / 15
Remainder: 2x3 = 6
Hence, C
Last edited by logitech on Mon Nov 24, 2008 9:10 am, edited 1 time in total.
LGTCH
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- logitech
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Sorry It was a typo. I was thinking of the result I edited my postTryingmybest wrote:Logitech- How did u get this? What is the significance of 6?
(15t+2) (15m+3) / 6
LGTCH
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I appreciate that. And also I want to thank moneyman for all of these great official questions.Tryingmybest wrote:Big Brother is watching u
And I know his test is very soon. GOOD LUCK man!
LGTCH
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Logitech -Sorry to bug u again
St 2) t=5b+3 ; t=3y ..5b+3 = 3y ...5b=3(y-1) and t = 15m + 3
If 5b=3(y-1) => t = 3(y-1)+3 how did u get t = 15m + 3??
Please enlighten me.
St 2) t=5b+3 ; t=3y ..5b+3 = 3y ...5b=3(y-1) and t = 15m + 3
If 5b=3(y-1) => t = 3(y-1)+3 how did u get t = 15m + 3??
Please enlighten me.
- logitech
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5b=3(y-1) well since 5b is also a multiple of 3
LCM(3:5) = 15
so for example
5x3 = 3 (6-1)
So this actually tells us 5b has 3 as a factor.
and t = 15m + 3
Did I confuse you even more ?
LCM(3:5) = 15
so for example
5x3 = 3 (6-1)
So this actually tells us 5b has 3 as a factor.
and t = 15m + 3
Did I confuse you even more ?
LGTCH
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Or in other words can I say
5b is a multiple of 3 => b must be a multiple of 3
=> 5b will be of the series 15,30,45 etc
=> 15 m (where m must be a multiple of 3)
It makes perfect sense now.. Thanks!!
5b is a multiple of 3 => b must be a multiple of 3
=> 5b will be of the series 15,30,45 etc
=> 15 m (where m must be a multiple of 3)
It makes perfect sense now.. Thanks!!