How to score a TEAS practice test?

I have the ATI version V book, and I took practice test one. But I'm not understanding how to score it. For example, for the reading part I got 8 wrong, so 34/42. What does that mean? If the test has a possible 170 items and 150 of them are scored, does that mean in theory that you could score a 150?

The school I am applying to says that want an "adjusted individual total score of 80%," and a "Cumulative Score TEAS 80" for a scholarship.

Thanks for your help!