Good practice - not comprehensive
I took the app exam 10 times over the past week and answered the same 15 questions EVERY time. The app only uses the sample questions at the back of the Utah Driver Handbook.
Fortunately, I already had a CA driver's license and was able to use the book during the 25 question exam. But if this is your first driver's license, you will be required to answer 55 questions without the book. Look for the 'DMV Test Prep - Utah' app to be better prepared.