My quant score in GMAT Focus Practice test 1 was 79 with 10 incorrect answers.
That seems an excessively generous score.
Questions 1 - 5 : correct
Questions 6 - 7: incorrect
Questions 8 - 10: correct (very behind on time already)
Question 11: incorrect (didn't read the question as the stem was too long)
Questions 12 - 13: correct
Questions 14 - 21: running out of time, answered A for all, one answer turned out right
For Question 8, I corrected the answer during review. I had realised my error immediately after submitting it.