There are several wrong answers in the answer key for the practice questions.
The instructors have informed staff of the problems and the answer keys are still not corrected a year later? Gee whiz guys. Maybe AWS should hire staff members with some back ground in welding, engineering, or someone that can do a simple math problem.
Well, I'm actually glad that if they don't have time to give an answer to my Official Interpretation request after 5 years that they can't fix a math problem on a practice key in just one year.