Edexcel D1 2007 January — Question 1

Exam BoardEdexcel
ModuleD1 (Decision Mathematics 1)
Year2007
SessionJanuary
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicSorting Algorithms
TypeBinary Search Execution
DifficultyEasy -1.8 This is a straightforward application of a memorized algorithm (binary search) to a small list with clear alphabetical ordering. It requires only procedural recall with no problem-solving, conceptual understanding, or mathematical reasoning—just following steps mechanically. Well below average difficulty for A-level maths.
Spec7.03a Algorithm definition: input, output, deterministic, finite
Use the binary search algorithm to try to locate the name NIGEL in the following alphabetical list. Clearly indicate how you chose your pivots and which part of the list is being rejected at each stage. 1. Bhavika 2. Clive 3. Elizabeth 4. John 5. Mark 6. Nicky 7. Preety 8. Steve 9. Trevor 10. Verity (Total 4 marks)
AnswerMarks
\(\left[\frac{1+10}{2}\right] = 6\) Nicola - reject top of listM1
\(\left[\frac{7+10}{2}\right] = 9\) Trevor - reject bottom of listA1
\(\left[\frac{7+8}{2}\right] = 8\) Steve - reject bottom of listA1
\([7+7] = 7\) Preety - rejectA1
Nigel not in list1c 
| $\left[\frac{1+10}{2}\right] = 6$ Nicola - reject top of list | M1 |
| $\left[\frac{7+10}{2}\right] = 9$ Trevor - reject bottom of list | A1 |
| $\left[\frac{7+8}{2}\right] = 8$ Steve - reject bottom of list | A1 |
| $[7+7] = 7$ Preety - reject | A1 |
| Nigel not in list | 1c |
Use the binary search algorithm to try to locate the name NIGEL in the following alphabetical list. Clearly indicate how you chose your pivots and which part of the list is being rejected at each stage.

1. Bhavika
2. Clive
3. Elizabeth
4. John
5. Mark
6. Nicky
7. Preety
8. Steve
9. Trevor
10. Verity

(Total 4 marks)

\hfill \mbox{\textit{Edexcel D1 2007 Q1}}
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