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Question 48

The subroutines Algorithm A and Algorithm B are designed to determine the number of half-lives required for an initial radioactive mass M M\,M to decay until it is less than or equal to a threshold mass TTT.

Algorithm A

SUBROUTINE simulateDecay(M, T)
  halfLives ← 0
  WHILE M > T
    M ← M / 2
    halfLives ← halfLives + 1
  ENDWHILE
  OUTPUT halfLives
ENDSUBROUTINE

Algorithm B

SUBROUTINE simulateDecay(M, T)
  halfLives ← 0
  REPEAT
    M ← M / 2
    halfLives ← halfLives + 1
  UNTIL M ≤ T
  OUTPUT halfLives
ENDSUBROUTINE

Describe two differences in the way the loops in Algorithm A and Algorithm B operate.

[3]
Markscheme

Programming concepts Questions

  1. GCSE
  2. /Computer Science
  3. /Programming concepts

298 exam-style questions on AQA GCSE Computer Science Programming concepts. Each one has a worked solution and a mark scheme showing where the marks go.

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