TExES Computer Science 8-12 (241)

1. Question 1 · Technology Applications Core

   A student saves an uncompressed bitmap image that is 800 pixels wide and 600 pixels tall using 24-bit color. Ignoring header data, how large is the file?
   • A.1,920,000 bytes
   • B.1,440,000 bytes
   • C.480,000 bytes
   • D.11,520,000 bytes
   Show answer and explanation

   Answer: B. 1,440,000 bytes

   The image has 800 × 600 = 480,000 pixels, and 24-bit color uses 3 bytes per pixel, so 480,000 × 3 = 1,440,000 bytes. The value 11,520,000 is the size in bits (480,000 × 24) mistakenly labeled as bytes; 1,920,000 bytes would correspond to 32-bit color.

2. Question 2 · Program Design and Development

   Insertion sort is applied to [7, 4, 9, 1, 6]. In each pass, the next unsorted element is inserted into its correct position in the sorted portion at the front. What is the array after exactly 3 passes (after the elements originally at indices 1, 2, and 3 have been inserted)?
   • A.[1, 4, 6, 7, 9]
   • B.[1, 4, 7, 9, 6]
   • C.[1, 4, 9, 7, 6]
   • D.[4, 7, 9, 1, 6]
   Show answer and explanation

   Answer: B. [1, 4, 7, 9, 6]

   Pass 1 inserts 4 to give [4, 7, 9, 1, 6]; pass 2 inserts 9, which stays put; pass 3 inserts 1 at the front to give [1, 4, 7, 9, 6]. The array [1, 4, 9, 7, 6] is what selection sort produces after two passes, and [4, 7, 9, 1, 6] is the state after only two insertion passes.

3. Question 3 · Program Design and Development

   Pythonhandlers = [] def on(fn): handlers.append(fn) def fire(x): for h in handlers: x = h(x) return x on(lambda v: v + 3) on(lambda v: v * 2) on(lambda v: v - 1) print(fire(4))

   What is printed when the Python code runs?
   • A.13
   • B.10
   • C.9
   • D.14
   Show answer and explanation

   Answer: A. 13

   fire runs the handlers in the order they were registered, passing each result to the next: 4 + 3 = 7, 7 × 2 = 14, and 14 − 1 = 13. Answering 14 stops before the last handler runs, and 9 applies the handlers in reverse order (4 − 1 = 3, 3 × 2 = 6, 6 + 3 = 9).

4. Question 4 · Programming Language Topics

   Pythoncalls = 0 def pos(v): global calls calls += 1 return v > 0 r = pos(-1) and pos(2) s = pos(3) or pos(-4) t = pos(5) and pos(-6) or pos(7) print(calls, r, s, t)

   Python evaluates and/or with short-circuiting, and and binds tighter than or. What does the code print?
   • A.7 False True True
   • B.6 False True True
   • C.5 False True False
   • D.5 False True True
   Show answer and explanation

   Answer: D. 5 False True True

   For r, pos(-1) is False, so pos(2) is skipped (1 call). For s, pos(3) is True, so pos(-4) is skipped (2 calls). For t, pos(5) and pos(-6) give False, so pos(7) is evaluated and returns True (5 calls total). Choosing 7 assumes every call runs, ignoring short-circuiting.

5. Question 5 · Programming Language Topics

   Pseudocodecount ← 0 for i ← 1 to n for j ← 1 to i for k ← 1 to 10 count ← count + 1 end for end for end for

   Loop ranges are inclusive. What is the time complexity of the pseudocode in terms of n?
   • A.O(n log n)
   • B.O(n²)
   • C.O(10n)
   • D.O(n³)
   Show answer and explanation

   Answer: B. O(n²)

   The innermost loop always runs a constant 10 times. The middle loop runs i times, so the total count is 10(1 + 2 + ... + n) = 10 · n(n + 1)/2, which is O(n²). Choosing O(n³) counts three nested loops without noticing that one of them has a fixed bound.

6. Question 6 · Technology Applications Core

   A computer lab uses the IPv4 network 192.168.10.0/24. How many addresses are available to assign to hosts?
   • A.255
   • B.254
   • C.65,534
   • D.256
   Show answer and explanation

   Answer: B. 254

   A /24 prefix leaves 8 host bits, giving 2^8 = 256 addresses; the all-zeros network address and the all-ones broadcast address cannot be assigned, leaving 254. The answer 256 forgets those two reserved addresses, and 65,534 is the count for a /16 network.

7. Question 7 · Program Design and Development

   Start. Set total to 0 and k to 1. Decision: is k > 10? If yes, output total and stop. If no, check whether k mod 3 = 0; if so, add k to total. Then add 2 to k and return to the decision.

   A flowchart is described as follows. What value is output?
   • A.12
   • B.25
   • C.18
   • D.3
   Show answer and explanation

   Answer: A. 12

   k takes the values 1, 3, 5, 7, and 9, and the loop stops when k becomes 11. Only 3 and 9 are divisible by 3, so total = 3 + 9 = 12. Answering 18 adds 3, 6, and 9, which assumes k increases by 1; answering 25 adds every odd value of k without applying the divisibility test.

8. Question 8 · Program Design and Development

   Pythonclass Button: def __init__(self): self.listeners = [] def add(self, fn): self.listeners.append(fn) def click(self): for fn in self.listeners: fn() log = [] b = Button() b.add(lambda: log.append("save")) b.add(lambda: log.append("beep")) b.click() b.listeners.pop(0) b.click() print(log)

   What is printed when the Python code runs?
   • A.['beep', 'save', 'beep']
   • B.['save', 'beep']
   • C.['save', 'beep', 'beep']
   • D.['save', 'beep', 'save']
   Show answer and explanation

   Answer: C. ['save', 'beep', 'beep']

   The first click calls both listeners in registration order, appending 'save' then 'beep'. pop(0) removes the first listener (the save callback), so the second click calls only the beep listener, giving ['save', 'beep', 'beep']. Answering ['save', 'beep', 'save'] assumes pop(0) removed the most recently added listener.

9. Question 9 · Programming Language Topics

   A program should display High only when the average total / count is greater than 50, and it must never divide by zero. AND and OR short-circuit from left to right. Which condition meets both requirements?
   • A.(count ≠ 0) AND (total / count > 50)
   • B.(total / count > 50) AND (count ≠ 0)
   • C.(count = 0) AND (total / count > 50)
   • D.(total / count > 50) OR (count = 0)
   Show answer and explanation

   Answer: A. (count ≠ 0) AND (total / count > 50)

   Placing count ≠ 0 first means that when count is 0, the AND is already false and the division is never evaluated. Reversing the order evaluates the division first and fails when count is 0. Testing count = 0 first with AND forces the division exactly when count is 0, and the OR version divides first.

10. Question 10 · Programming Language Topics

    Javaint work(int n) { int c = 0; for (int i = 1; i < n; i *= 2) { for (int j = 0; j < n; j++) { c++; } } return c; }

    What is the time complexity of the Java method in terms of n?
    • A.O(n²)
    • B.O(n log n)
    • C.O(log n)
    • D.O(n)
    Show answer and explanation

    Answer: B. O(n log n)

    The outer loop doubles i (1, 2, 4, ...) until it reaches n, so it runs about log₂ n times. The inner loop runs n times on every outer pass regardless of i, giving about n · log₂ n operations, which is O(n log n). Choosing O(n²) treats both loops as linear without noticing the doubling update.

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