I bought the book at Barnes and Noble. Thought it may be helpful.
It is not a bad book in terms of quant, but the RC and CR are simply horrible. They ask you to make too many judgement calls and to bring in extraneous information. I did this book last week. I thought I had gotten dumber.
I did the RC in OG 11. I missed a total of 4 out of 140.
So obviously the questions in the Arco book are poor questions and not up to GMAT standards..

Don't use the book. It will ruin your confidence