A-LevelComputer ScienceHardware9618/33 · May/June 2025 · Q38 Marks

This truth table represents a logic circuit.

(a)Write the Boolean logic expression that corresponds to the given truth table as the sum-of-products. Z =[2]
(b)(i)Complete the Karnaugh map (K-map) for the given truth table.[2]
(b)(ii)Draw loop(s) around appropriate group(s) in the K-map to produce an optimal sum-of-products.[2]
(b)(iii)Write the Boolean logic expression from your answer to part (b)(ii) as the simplified sum-of-products. Z =[2]

This question uses a diagram from the original paper, which isn't shown here. Open the full paper from the past papers archive to see it.

Mark scheme

Marking points from the official mark scheme (May/June 2025). The mark or mark type is shown in brackets.

[2] Two marks for all six correct terms
[1] One mark for any four correct terms
z = Ā.B.c.D + Ā.B.C.D + Ā.B.C.D + A.B.C.D + A.B.C.D + A.B.C.D
[2] Two marks if no errors present
[1] One mark if one error present
K-map with values: AB\CD | 00 | 01 | 11 | 10 ---|---|---|---|--- 00 | 0 | 0 | 1 | 1 01 | 1 | 1 | 0 | 0 11 | 1 | 0 | 0 | 1 10 | 1 | 0 | 0 | 1
[2] One mark for each correct loop (Max 2)
Loops drawn as in mark scheme example diagram
[2] One mark for each mark point
• One correct Boolean term
• Boolean terms and operator correct and no other terms present
z = B.C + B.C.Б // B.С.Б + B.C

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