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by akhpad » Mon Apr 26, 2010 12:40 am
Statement 1:

m = 2a, p = 2b where a and b both are co-prime

(m, p) could be (4, 6), (4, 10)

Remainder should be 2 or more, as both are multiple of 2

Sufficient

Statement 2:
30 = 2*3*5
(m, p) could be (3, 10), (3,5) ,(5,6), (6,15)

Remainder can be 1, 2, 3 or even more

Insufficient

Answer: A
Last edited by akhpad on Tue Apr 27, 2010 7:42 pm, edited 2 times in total.

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by clock60 » Tue Apr 27, 2010 12:19 pm
akhp77 wrote:Statement 1:

m = 2a, p = 2b where a and b both are different prime nos

(m, p) could be (4, 6), (4, 10)

Remainder should be 2 or more, as both are multiple of 2

Sufficient

Statement 2:
30 = 2*3*5
(m, p) could be (3, 10), (3,5) ,(5,6), (6,15)

Remainder can be 1, 2, 3 or even more

Insufficient

Answer: A
hi akhp77
i really like you solution
but only one question, how did you come that a=2m, and p=2b where both a and b are both prime numbers
to me only one m must be prime
for example 14=2*7 and 16=2*8
or i am missing something?

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by kevincanspain » Tue Apr 27, 2010 3:58 pm
You are right, a and b need not be different prime numbers but rather two different integers greater than 1.


Here's a nice rule to keep in mind.: If a and b are two positive integers that have a common factor of c, the remainder when a is divided by b must be a multiple of c.

For example, when a multiple of 18 is divided by 30, the remainder must be a multiple of 6 (i.e. 0,6,12,18 or 24) , since GCF(18,30) = 6.

Similarly, when a multiple of 155 is divided by 210, the remainder must be a multiple of 5 (i.e. 0 , 5 , 10 ,..., 205) since GCF (155,210) = 5.

Question: If x is a positive multiple of 38, and r is the remainder when x is divided by 54, how many possible values of r are greater than 46?
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by akhpad » Tue Apr 27, 2010 5:32 pm
clock60 wrote:
akhp77 wrote:Statement 1:

m = 2a, p = 2b where a and b both are different prime nos

(m, p) could be (4, 6), (4, 10)

Remainder should be 2 or more, as both are multiple of 2

Sufficient

Statement 2:
30 = 2*3*5
(m, p) could be (3, 10), (3,5) ,(5,6), (6,15)

Remainder can be 1, 2, 3 or even more

Insufficient

Answer: A
hi akhp77
i really like you solution
but only one question, how did you come that a=2m, and p=2b where both a and b are both prime numbers
to me only one m must be prime
for example 14=2*7 and 16=2*8
or i am missing something?
You are right.
I have edited that,

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by harshavardhanc » Wed Apr 28, 2010 12:52 am
kevincanspain wrote:
Question: If x is a positive multiple of 38, and r is the remainder when x is divided by 54, how many possible values of r are greater than 46?
[spoiler]
3? 48,50,52[/spoiler]
Regards,
Harsha

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by kevincanspain » Wed Apr 28, 2010 8:19 am
Right!
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