The passing score in Iowa is 80 percent. It means you should answer at least 28 out of 35 questions correctly to pass both this practice test and the real DMV test.
The safest tactic, however, is to aim for a full score on each DMV practice test.
Take as many tests as you need to feel comfortable with all answers. Learn by your mistakes. If needed, use the DMV Driver's Manual and read up on the facts.
The more practice tests you take, the more you cover of the Iowa Driver's Manual and the easier the real test will be.
Each question on the test is followed by instant feedback (right or wrong). If you get it wrong, there is a brief explanation. Keep your Handbook handy and compare the explanation with the information in the Handbook.
If two answers seem plausible, you are missing something. Read everything again and make sure you understand why the other options are incorrect - because they are.
If you need to guess at the practice test, it is a strong signal that you need to read up on that subject in the driver's manual.Pay attention to key words. Closed words (such as never, only, always, all, none, and most) are often (but not always!) indicators of a false statement because they restrict possibilities. Open words (such as usually, frequently, mostly, often, and generally) are often (but not always!) found in true statements.
Even if all test questions and answers are carefully reviewed and verified against the Iowa Driver's Manual and State laws, there is always a risk of errors in a test when rules change. Let us know if you find something we have missed in our practice tests and we will correct it!
There are many articles on driversprep.com that can help you learn more.
A basic rule in education is that the you cannot really learn anything if you just remember isolated facts and try recall them for a test. You need to connect the dots and understand how facts can be used in real life, or in this case, how they will help you on the road.