Not possible, but if there are any answer choices please add them in the comments below.
Step-by-step explanation:
In order for you to get 45 questions correct you wouldn't have enough questions on the test to do so, because as you've stated there are only 20 questions on the test, so you would need to complete more than one test.
If this is the case then you would need to complete 3 tests of 20 questions. and get 15 questions right on each test to get 45 questions correct in total.
