2 questions

[Daniel Lucas]

Alright I'm doing two AP test questions, and they both use the same code segment. Here it is(my analysis is below):

Questions 8-9 refer to the following incomplete class declaration.
 
public class TimeRecord
{
private int hours;
private int minutes;  // 0 <= minutes < 60
 
public TimeRecord(int h, int m)
{
hours = h;
minutes = m;
}
 
// postcondition: returns the 
// number of hours
public int getHours()
( /* implementation not shown */ }
 
// postcondition: returns the number
// of minutes; 0 <= minutes < 60
public int getMinutes()
{ /* implementation not shown */ }
 
// precondition: h >= 0; m >= 0
// precondition: adds h hours and
// m minutes to this TimeRecord
public void advance(int h, int m)
{
hours = hours + h;
minutes = minutes + m;
 
/* missing code */
}
 
// ... other methods not shown
 
8. Which of the following can be used to replace /* missing code */ so that advance will correctly update the time?
 
(A) minutes = minutes % 60;
(B) minutes = minutes + hours % 60
(C) hours = hours + minutes / 60;
minutes = minutes % 60;
(D) hours = hours + minutes % 60;
minutes = minutes / 60;
(E) hours = hours + minutes / 60;
 
9. Consider the following declaration that appears in a client program.
 
TimeRecord[] timeCards = new TimeRecord[100];
 
Assume that timeCards has been initialized with TimeRecord objects. Consider the following code segment that is intended to compute the total of all the times stored in timeCards.
 
TimeRecord total = new TimeRecord(0, 0);
 
for (int k = 0; k < timeCards.length; k++
{
/* missing expression */;
}
 
Which of the following can be used to replace
/* missing expression */ so that the code segment will work as intended?
 
(A) timeCards[k].advance()
(B) total += timeCards[k].advance()
(C) total.advance(timeCards[k].hours,
timeCards[k].minutes)
(D) total.advance(timeCards[k].getHours(),
timeCards[k].getMinutes())
(E) timeCards[k].advance(timeCards[k].getHours(),
timeCards[k].getMinutes())

My analysis for question 8:

This is just a mathematical equation that's missing. First thing I notice is it needs to declare what both hours and minutes are, so it needs to be C or D. The only difference between C and D is C uses division whereas D uses modulus. Using modulus would be incorrect because say you had 3 hours + 90 minutes % 60, you would get 3 + 30, which is incorrect. So the answer must be C. *checks answer* yep, it's C.

My analysis for question 9:

Again I need to figure out which answer choice can be used to replace the missing expression to make it work as intended. In this case I'm missing the expression within the for statement. The intention is to compute the total of all the times stored in timeCards. So let's look at the answer choices:

A. This has no mathematical expression to compute the total.
B. This does not specify the format for the total.
C. C and D look like what we're trying to get, but it is necessary since the user is not inputting the hours and minutes to get them.
D. This answer choice gets the hours and minutes, making it the best answer choice IMO.
E. This does not even show a total, and is similar to D.

So I'm going to go with D. Am I right? *checks answer* Yep, it's D. Dunno if my reasoning is correct though