BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

GMATPrep

Expert replies
Source: — Data Sufficiency |

by cris » Sun Jan 27, 2008 7:47 pm
This question is really confusing, "least common denominator" is not HCF or LCM...Least common denominator of anything should be 1...

Calista are you sure you copied that correctly??
Join the discussion

by malnv » Sun Jan 27, 2008 8:00 pm
Least Common denominator is usually applied to fractions. We unknowingly do L.C.D all the time when adding fractions

From the Q..

1. x/y + 1/3 has L.C.D. of 6 .
i.e. L.C.M (y,3) = 6 which gives y =2 (if the fraction is in reduced form)

But, x/y can be 2/4, which makes y =4..

So Not SUFF


2. x= 1, no way to find y.


Combining 1 & 2, y =2
SUFF

ANS: C

let me know if it matches with OA.
Join the discussion

by cris » Sun Jan 27, 2008 8:08 pm
we do the Least Common Multiple when adding fractions....

Correct me if i am wrong.
Last edited by cris on Sun Jan 27, 2008 10:42 pm, edited 3 times in total.
Join the discussion

by simplyjat » Sun Jan 27, 2008 8:55 pm
L.C.M (y,3) = 6 which gives y =2 (if the fraction is in reduced form)
This interpolation is incorrect y can be 6 as well...
simplyjat
Join the discussion

by malnv » Sun Jan 27, 2008 9:03 pm
You are right.. Its a possibility..

So combining 1 & 2, y can be either 2 or 6.

So it should be E.

Looks like i need to spend few seconds extra before i conclude :)

Thx for catching!
Join the discussion

by StarDust845 » Mon Jan 28, 2008 9:41 am
Yeah I too was confused with the question. But the question is correct and I think malnv's solution is good.

So rephrasing is LCD just LCM of denomitors?

Calista.
Join the discussion

by simplyjat » Mon Jan 28, 2008 10:22 pm
E is the correct answer for the question...
Thanks for updating the solution malnv
simplyjat
Join the discussion