A new character set must be able to represent 70 different characters.
Identify the minimum number of bits needed to represent each character.
Mark scheme
- B 7 (1)
- The only correct answer is B. The correct answer is 7.
- A is not correct because 6 bits give only 64 combinations, which is not enough for 70 characters
- C is not correct because 7 bits already give 128 combinations, so 8 bits is not the minimum needed
- D is not correct because 70 is the number of characters needed, not a number of bits
Example answers and how they were marked
Full marks1/1
B 7
Why: The only correct answer: 7 bits give 128 combinations, enough for 70 characters, and it is the smallest number of bits that does (1).
No marks0/1
C 8
Why: Distractor, no credit: a single-tick item has no partial credit, and 8 bits is not the minimum because 7 bits already give 128 combinations, so the scheme's C line gives no mark.
No marks0/1
A 6
Why: Misconception, no credit: 6 bits give only 64 combinations, which cannot represent 70 different characters, so the scheme's A line gives no mark.