Lesson 4.4.1.1

4.4.1.1 Problem-solving and algorithms Quiz: AQA Computer Science, Unit 4

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 4.4.1.1, Problem-solving and algorithms: 20 multiple choice questions for the AQA Computer Science (7517), Unit 4: Theory of computation, written with Revision Ninja.

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The 20 questions

  1. According to the specification, what key property must every algorithm possess alongside completing a task?

    • It uses pseudo-code
    • It uses recursion
    • It executes concurrently
    • It always terminates

  2. Which programming construct is NOT one of the four standard pseudo-code constructs specified?

    • Iteration
    • Recursion
    • Selection
    • Sequence

  3. What must an algorithm always do for any valid input?

    • Return an integer
    • Terminate
    • Loop indefinitely
    • Use recursion

  4. Which of these is NOT one of the standard pseudo-code constructs in the specification?

    • Assignment
    • Garbage collection
    • Selection
    • Iteration

  5. What graphical technique uses boxes and arrows to represent program flow and operations?

    • Flowchart
    • Karnaugh map
    • State transition diagram
    • Syntax tree

  6. What is manually tracking variable values step-by-step through an algorithm called?

    • Syntax checking
    • Dry-compiling
    • Hand-tracing
    • Code profiling

  7. Trace: x = 3, then while x < 10 set x = x * 2. What is the final value of x?

    • 6
    • 8
    • 10
    • 12

  8. Algorithm: total = 0, then for i from 1 to 4 add i to total. What is the final total?

    • 4
    • 10
    • 24
    • 7

  9. Ann, Ben and Cat: exactly one of them tells the truth. Ann says Ben is lying. Ben says Cat is lying. Cat says Ann and Ben are both lying. Who tells the truth?

    • Ann
    • Ben
    • Cat
    • No one

  10. How many times is the body of 'for i = 1 to 5' executed?

    • 1
    • 4
    • 5
    • 6

  11. Which pseudo-code selection correctly tests whether the integer n is even?

    • IF n MOD 2 = 0 THEN
    • WHILE n = 2
    • n = n MOD 2 ENDIF
    • IF n DIV 2 THEN

  12. An algorithm finds the largest of a list of 7 values by comparing each item with the current maximum. How many comparisons are made?

    • 7
    • 8
    • 6
    • 49

  13. Which type of test data is essential for revealing edge-case bugs in a sorting algorithm?

    • Unsorted text array
    • Empty list
    • Large random list
    • List of integers

  14. Why would a process containing an infinite loop for a valid input fail to be an algorithm?

    • It lacks variables
    • It never terminates
    • It lacks outputs
    • It uses selection

  15. What predicate condition remains true before and after each loop iteration to help prove loop correctness?

    • Loop variant
    • Base case
    • Exit condition
    • Loop invariant

  16. Does a procedure that fails to halt on certain valid inputs qualify as an algorithm?

    • Yes
    • Only if compiled
    • No
    • Only in pseudo-code

  17. How many different orderings are there of three distinct items?

    • 9
    • 3
    • 6
    • 27

  18. Trace the sequence: start with n = 12. While n > 1, halve n if it is even, otherwise set n = 3n + 1, counting each step. How many steps reach 1?

    • 7
    • 9
    • 5
    • 12

  19. Algorithm A takes 100 steps while Algorithm B takes 10 steps for the same input. Why is B preferred?

    • Fewer variables
    • Higher time efficiency
    • Better accuracy
    • Lower space complexity

  20. Which design technique breaks down a complex problem into smaller, manageable sub-problems?

    • Backtracking
    • Decomposition
    • Abstraction
    • Memoisation

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