The Official Guide Companion (Edition 4.x)

Cover for 4th Edition

Edition 4.1	Edition 4.0
Release Date: March 21, 2009 Differentiating Mark: Back Cover, Bottom Right Corner	Release Date: May 1, 2009

This book is designed to be used in conjunction with the Official Guide for GMAT Review, 12th Edition, the primary resource for those studying for the GMAT. In the Official Guide Companion, every quant question in the 12th Edition is broken down and thoroughly explained – that’s over 450 comprehensive explanations.

4.1

Page	Loc	Description	Erroneous Text	Correction
237	Bot	In the explanation for DS 170, the expression is incorrectly factored.	n3 – n. n(n2 – n)	n3 – n. n(n2 – 1)
234	Mid	The explanation for statement 2 mistakenly says that the account would contain $2,800. It should say that the account would contain $2,720.	…his balance would have been $2,800.	…his balance would have been $2,720.
39	Bot	Misprint in the second sentence of the explanation of (1) and (2) together.	We and from Statement (1) that x is less than y, then x must be negative.	We also know from Statement (1) that x is less than y.
30	Bot	In the chart used to evaluate statement (2), The entry for n = 6 is incorrect.	Yes, so n can be 3 (stop)	Yes, so n can be 6 (stop)
202	Bot	In the diagram for #102, the labels on the cars are reversed. Car X should be in front of car Y.
30	Bot	In the chart used to evaluate statement (2), The entry for n = 4 is incorrect.	No, so n can't be 4.	Yes, so n can be 4.
187	Mid	In the chart used to evaluate statement (2), No and Yes should be switched in the final column.
191	Bot	Every “>” in the explanation for DS 80 should be replaced with “<".
97	Bot	In the third paragraph of the explanation for PS 121, “N” and “Y” are switched.	We divide by 2! and 6! to take into account that the 2 N's and 6 Y's are identical.	We divide by 2! and 6! to take into account that the 2 Y's and 6 N's are identical.
76	Top	In the last paragraph of the explanation for PS 75 (and the preceding equation), replace 2/3 with 1/3.	40 × (1/3) = 40/3 = 13 (2/3) Again, we cannot have a fraction of a person, and since no more than 13 (2/3) can vote against the resokution, a maximum of 13 people can vote against it. Be sure not to round 13 (2/3) up to 14, which is a trap answer.	40 × (1/3) = 40/3 = 13 (1/3) Again, we cannot have a fraction of a person, and since no more than 13 (1/3) can vote against the resokution, a maximum of 13 people can vote against it. Be sure not to round 13 (1/3) up to 14, which is a trap answer.
189	Mid	In the explanation for Statement 1, the equation '300 + 0.05(1,000 – x) = 0.10x' appears twice. In both instances, the terms in parentheses (1,000 – x) should read (x – 1,000).	300 + 0.05(1,000 – x) = 0.10x	300 + 0.05(x – 1,000) = 0.10x