Are you saving those GMAT Prep tests for a retake?

V42 means you get a 96th percentile in Verbal. Those are HIGH expectations. You want to perform better than 96% of people on the GMAT but you want to use the least accurate calculation to get there... Someone who is ranked 4th in the world in Tennis, will not be picking up a Walmart racket for their Wimbledon match.
If you were targeting Q35, then maybe you can a back of napkin evaluation approach but Q40+ is very very hard to estimate without taking a test (I would say you have to get 9 out of 10 random difficulty questions right to be at that level). By the way, as an immediate let down, the score does not depend on the number of questions you get right. You can check this topic:
https://gmatclub.com/forum/new-format-g ... 69682.html there is no dividing 34 by 36 or anything like that. Don't even bother. There are many aspects that impact GMAT - timing and pacing yourself, when and where in the test you mess up, how you recover, and how many hard questions you ultimately answer. Moreover, an important role is played by the test you take and their question database. If you have a test such as GMAT Prep 3, 4, 5, 6 with very shallow pool of questions, you can make just 2 mistakes and get a V40 because most of them are easy but then you can take GMAT prep and make 9 mistakes and get V42. you can also get a V30 with 9 wrong. It is all in that topic for your enjoyment