value of xy? (GMAT Prep 2)

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Source: — Data Sufficiency |

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by Anurag@Gurome » Sat Jul 21, 2012 1:47 am
alex.gellatly wrote:If x and y are positive integers, what is the value of xy?

1. The greatest common factor of x and y is 10.
2. The least common multiple of x and y is 180
Product of two positive integers = (LCM of the integers)*(GCF of the integers)
Hence, we need both the statements to answer the question.

The correct answer is C.
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by Anurag@Gurome » Sat Jul 21, 2012 1:56 am
Picking Numbers:
Statement 1: Consider the following two cases,
  • x = 10 and y = 20 ---> xy = 200
    x = 10 and y = 30 ---> xy = 300
Not sufficient

Statement 2: Consider the following two cases,
  • x = 4 and y = 45 ---> xy = 180
    x = 90 and y = 180 ---> xy = 90*1800
Not sufficient

1 & 2 Together: xy = 10*180 = 1800
Sufficient

The correct answer is C.
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