Computer Science
Assignment
1. A variety of goods stored in a warehouse. All goods are bar coded. The number of each
item in the warehouse is stored as a binary number.
(a) Change 125 into a binary number stored in an 8 bit byte. Show your working.
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Your Answer: (
[2]
)2
(b) Convert your answer in question 1. (a), into hexadecimal number. Show your
working.
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Your Answer: (
[2]
)16
(c) Convert your answer in question 1. (b) into denary (decimal) number. Show your
working.
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Your Answer: (
)10
[2]
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2.
2. A vending machine has the choices shown below
A customer uses a keypad to make their choice. Each number entered is represented in
a 6-bit binary register.
For example, key press 33 (hot chocolate with extra milk and extra sugar) is represented
by:
(a) (i) If a customer chooses coffee with milk and sugar what is the key press?
[1]
(ii) How is it represented in the 6-bit register?
[1]
(b) If the 6-bit register shows
What drink has the customer chosen?
[1]
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(c) A customer using the vending machine gets an error message after keying in their
selection.
What could have caused this error message?
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[1]
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(d) It was decided to split the register so that each digit was represented by its own 3-bit
register:
(i) What drink has been chosen if the 3-bit registers contain:
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[1]
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(ii) How would the lemon option be shown on both types of register?
[2]
(iii) What is the advantage of using two 3-bit registers rather than one 6-bit
register?
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[1]
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