Computer Science · May / June 2025 · Paper 22 · Question 8

One mark for the logic gate and one mark for the truth table

XOR logic gate symbol:

Truth table:

A

B

X

0

0

0

0

1

1

1

0

1

1

1

0

One mark per mark point

MP1 A AND

MP2 (NOT B OR NOT C) // NOT(B AND C) // (B NAND C)

Or

One mark per mark point

MP3 A AND NOT B

MP4 OR A AND NOT C

Example answers

(X =) A AND (NOT B OR NOT C) // A AND NOT (B AND C) // A AND (B NAND C)

(X =) A AND NOT B OR A AND NOT C

Four marks for eight correct outputs

Three marks for six or seven correct outputs

Two marks for four or five correct outputs

One mark for two or three correct outputs

A

B

C

X

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0

0

0

1

0

0

1

0

0

0

1

1

0

1

0

0

1

1

0

1

1

1

1

0

1

1

1

1

0