The airport has touchless handwashing stations - Edexcel - GCSE Computer Science - Question 3 - 2020 - Paper 1
Question 3
The airport has touchless handwashing stations. The stations automatically dispense soap, water and warm air for drying. To conserve water, the stations must ensure ... show full transcript
Worked Solution & Example Answer:The airport has touchless handwashing stations - Edexcel - GCSE Computer Science - Question 3 - 2020 - Paper 1
Step 1
3a: Identify the sensor used for water dispensing
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Answer
SENSOR_W
Step 2
3b: Explain the issue in the algorithm regarding operations
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Answer
The algorithm would allow for two operations to be carried out at the same time, contradicting the requirement that only one operation should occur at any given moment.
Step 3
3c: Correcting the soap dispensing condition in the algorithm
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Answer
To ensure exclusive operation, the condition should be adjusted as follows:
IF (soapRequest = True) THEN
SET soapStatus TO "on"
ELSE
SET soapStatus TO "off"
END IF
Step 4
3d: Provide the correct logical structure for exclusive operation
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Answer
The proper structure to ensure mutual exclusivity for the operations is:
NOT (soapRequest AND waterRequest AND dryerRequest)
OR
(NOT soapRequest AND NOT waterRequest AND NOT dryerRequest)
