Test Corrections

• The AP Collegeboard Test
  • Question 22
  • Question 28
  • Question 34
  • Question 35
  • Question 38
  • Question 39
  • Question 40

The AP Collegeboard Test

For our final for APCSA trimester one, we had to take a test on college board on crucial concepts in Java. I got 33/40, which still gets me 100% in the class, but these are the corrections for the 7 questions I missed.

Question 22

I got this question wrong because I thought that you had to specify a method would be overriden when creating a new function in the child class with the same method signature as a function in the parent class. However, this was wrong. That’s why D is wrong.

My other mistake was that I didn’t realize that, since books only takes in a list of the object Book, using a child class AudioBook to create an object in the list is valid, but it’ll only be considered as a Book and will be unable to access methods unique to its child class. That’s why the correct answer is B, because books[0] can’t access methods that are in the child class.

Question 28

I’m not exactly sure why I got this wrong, but I think it’s because I thought the loop would always run, therefore x would never be equal 1 after the loop, which is false, because n can be given a value less than 2. That’s why B is wrong.

E is right because the conditions for the loop to run necessitates that n is greater than 2, therefore it’ll always be greater than 2 inside the loop.

Question 34

I don’t know why I got this question wrong. I realized that I wouldn’t work because it never sets the center point and III wouldn’t work because the Circle class can’t access private attributes, but I still chose the wrong answer. I think I just misclicked.

Question 35

I got this question wrong because I forgot to consider result * 10 in the reassignment of result. I thought that the program simply summed up the digits in the number, which is why I chose 18. But result * 10 actually means that the digits in the number are being switched around, which is why 4752 is the right answer.

Question 38

I got this question wrong because I forgot to consider that y being greater than 10000 is not necessary for the expression to evaluate to be true. My response does evaluate to true if y > 10000, but I forgot that the other conditions of x < 1500 and x > 1000 can also be true to make the expression evaluate to be true.

Option A does consider both of these options, which is why it’s the correct answer.

Question 39

This question was really hard for me. The double recursion made things super confusing for me, until I realized that the loop of recursion would continue until n was less than or equal to 10. I thought that the answer must be less than 10, which is why I chose 8, but I forgot to realize it would multiple it by 2 one last time before returning n, which is why 16 is actually the right answer.

Question 40

I didn’t realize that the program would print temp instead of the original string, which is why I thought it would still print “WATCH” at the end and not just “WATC”. That’s why Option C is the right answer and not Option D.