Source: Official Guide for the GMAT 13th Ed. Data Sufficiency; #67 Official Guide for the GMAT 2015 14th Ed. Data Sufficiency; #67
Felipe Levi Gurgel
I didnt understand something.
1- result of n(n+1)= 6 would be N^2 + N= 6 and the only result possible here to come to 6 would be 2^2 + 2 = 6, than n=2.
Where is it wrong???
Dec 23, 2016 • Comment
Sam Kinsman
Hi Felipe,
Actually, n could also be equal to -3. That would work as well.
We can find this by factoring:
N^2 + N= 6 N^2 + N - 6 = 0 (N + 3) (N - 2) = 0
So N can be either 2 or -3.
Dec 27, 2016 • Reply
Mike McGarry, Magoosh Tutor
Jan 4, 2014 • Comment
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