2020 O/L ICT Past Paper and Answers | English Medium

7th question is missing!

I just wanted to point out an error in the marking scheme. The answer for the 37th question in the MCQ paper is 4. 55 not 1.25. I don’t know how this error occurred, but I think they ignored the fact that a “REPEAT UNTIL” loop never stops its execution until the condition that’s been given to it becomes false. In this case, UNTIL count > 0 implies that the value of “sum” will increase to a value greater than 25 because the loop will run the code inside it until count is equal to zero. When count is equal to zero, the value of sum is displayed and that’s the final output.

Here’s a more detailed explanation:
The answer provided in the marking scheme (25) is incorrect because the loop does not terminate after the first iteration. In the pseudocode, the REPEAT…UNTIL loop runs until the condition count > 0 is false. Since the initial value of count is 5, the loop executes multiple times, decrementing count and adding count^2 to sum in each iteration.

The correct calculation is as follows:

Iteration 1: sum = 0 + 5^2 = 25, count = 4
Iteration 2: sum = 25 + 4^2 = 41, count = 3
Iteration 3: sum = 41 + 3^2 = 50, count = 2
Iteration 4: sum = 50 + 2^2 = 54, count = 1
Iteration 5: sum = 54 + 1^2 = 55, count = 0
The loop exits when count = 0, as count > 0 is now false. Thus, the output of the program is 55, not 25. This mistake likely stems from misunderstanding how the UNTIL condition functions.