Hello, George. It is not possible to give an estimate of the number of questions you can get wrong and still receive a 40 or higher, because there are too many factors that contribute to your score. I can share with you some general data about test-takers who received a 700 or higher on the GMAT exam in 2011:

For the 25,800 calendar year 2011 test takers scoring 700 and above, the mean (and standard deviation) of the number of correct answers were 31.6 (3.6) and 29.9 (4.0) for Verbal and Quant, respectively. The minimums were 19 and 17 respectively.

As always, the best way to get a 40+ on the verbal section is to prepare thoroughly, and familiarize yourself with the test format and timing.