In the fraction x/y, where x and y are positive integers, wh

[victorgsiu]

In the fraction x/y, where x and y are positive integers, what is the value of y?

1) The least common denominator of x/y and 1/3 is 6.
2) x = 1

Statement 2)
Says nothing about y, insufficient.

Statement 1)
rephrase: the LCM of y and 3 is (2)(3). Draw an LCM chart. 3 has one (3), so y MUST have one (2). additionally, y may also have an additional (3), without changing the LCM. Therefore, y can be (2) OR (2)(3). Insufficient.

Together)
y = (2) or (2)(3)
x = 1, does not affect the denominator.
Still insufficient. E.

Was what I did in Statement 1 appropriate, and did I solve this problem in the best way possible?

[agha79]

I agree with your approach for statment one. Thats what i did as well and got to "E"

[Ben Ku]

Your approach is good!

[mariabfa]

I don't understand Statement 1 - could you explain? Thanks!

[vijay.gmat2011]

Your approach is correct except there is one more possibility for y: 6

[RonPurewal]

note also that the numbers "3" and "6" are really small, so you can just think about the possibilities.
if you think about the possibilities that will generate a LCD of 6, you should realize the following:
* they both have to go into 6 ... so they must be 1, 2, 3, or 6.
* one of them is 3. (this is given)
* the other one can't be 3 or 1, since those possibilities would give a LCD of 3 rather than 6.
* so, that means the denominator of the other fraction must be either 2 or 6.

at this point, you can just examine the most elementary possibilities -- namely, 1/2 and 1/6 -- and that's enough to conclude that the answer is (e).

[sachin.w]

Sir Ron,

Though I understand the soln to this Question, I would like to know if we need to learn finding LCM of fractions..

Kindly guide us.

Regards,
Sach

[jlucero]

Sir Ron,

Though I understand the soln to this Question, I would like to know if we need to learn finding LCM of fractions..

Kindly guide us.

Regards,
Sach

LCM = least common multiple (multiple is a whole integer)
LCD = least common denominator (bottom of a fraction)

It's impossible to find the LCM of a fraction, because fractions are generally not whole numbers. But knowing your LCMs and LCDs are both crucially important for the GMAT.

[sachin.w]

Sir Ron,

Though I understand the soln to this Question, I would like to know if we need to learn finding LCM of fractions..

Kindly guide us.

Regards,
Sach

LCM = least common multiple (multiple is a whole integer)
LCD = least common denominator (bottom of a fraction)

It's impossible to find the LCM of a fraction, because fractions are generally not whole numbers. But knowing your LCMs and LCDs are both crucially important for the GMAT.

Ok.. Thanks a lot.. I actually misinterpreted LCD as LCM.. :D

[jnelson0612]

Sir Ron,

Though I understand the soln to this Question, I would like to know if we need to learn finding LCM of fractions..

Kindly guide us.

Regards,
Sach

LCM = least common multiple (multiple is a whole integer)
LCD = least common denominator (bottom of a fraction)

It's impossible to find the LCM of a fraction, because fractions are generally not whole numbers. But knowing your LCMs and LCDs are both crucially important for the GMAT.

Ok.. Thanks a lot.. I actually misinterpreted LCD as LCM.. :D

Glad that things are straightened out for you! :-)