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If m and n are positive integers

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If m and n are positive integers

by mangomangodolly » Mon Nov 26, 2012 9:54 am
If m and n are positive integers, then lcm(m,n) denotes the least common multiple of m and n. Let x be a positive integer and y be a positive integer. What is the value of x?

(1) lcm(x,y) = 5y

(2) lcm(x, lcm(x,y)) = 300

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
D. EACH statement ALONE is sufficient.
E. Statements (1) and (2) TOGETHER are NOT sufficient.
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Source: — Data Sufficiency |
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by jkaustubh » Mon Nov 26, 2012 8:29 pm
IMO, the answer can be A

not sure though, what is the OA?
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by tinashine20 » Mon Nov 26, 2012 8:45 pm
Please provide official answer, this question is quite intresting.
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by sanrisenew » Mon Nov 26, 2012 11:33 pm
1. LCM of x,y is 5y ,here we can assume x= 5.a & y = k.a; in this scenario LCM would be 5.k.a= 5y= k.x
Therefore depending on value of a, x can assume multiple values hence insufficient.
2. lcm(x, lcm(x,y)) = lcm(x,y) = 300
for 300 to be lcm of two numbers there are couple of contenders (12,25);(4,75)

hence IMO E
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by Brent@GMATPrepNow » Tue Nov 27, 2012 4:51 pm
mangomangodolly wrote:If m and n are positive integers, then lcm(m,n) denotes the least common multiple of m and n. Let x be a positive integer and y be a positive integer. What is the value of x?

(1) lcm(x,y) = 5y
(2) lcm(x, lcm(x,y)) = 300
Target question: What is the value of x?

Statement 1: lcm(x,y) = 5y
There are several pairs of numbers that meet this condition. Here are two:
Case a: x=300 and y=60. Here, the LCM is 300, and 300 equals 5y
Case b: x=150 and y=60. Here, the LCM is 300, and 300 equals 5y Since we cannot answer the target question with certainty, statement 1 is NOT SUFFICIENT

Statement 2: lcm(x, lcm(x,y)) = 300 There are several pairs of numbers that meet this condition. Here are two:
Case a: x=300 and y=60.
Case b: x=150 and y=60.
Since we cannot answer the target question with certainty, statement 2 is NOT SUFFICIENT

Statements 1 and 2 combined:
Case a: x=300 and y=60.
Case b: x=150 and y=60.
Since we cannot answer the target question with certainty, the combined statements are not SUFFICIENT

Answer = E

Cheers,
Brent
Last edited by Brent@GMATPrepNow on Thu Sep 03, 2015 1:37 pm, edited 1 time in total.
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by J N » Fri Mar 22, 2013 12:35 pm
did you mean 150 and 30
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