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Grade 9 · Computer science

Grade 9 Computer science diagnostic

15 questions on algorithms & logic, digital literacy, data systems and data structures, plus 3 from Grade 8. Answer what you can, then check your answers to see which topics are secure and what to practise next.

15 questions4 topicsAbout 15 minutesSet 4 of 5

Skip a question if you do not know the answer. It is better than guessing, because it shows what to practise.

1Algorithms & logicUsing zero-based indexing, what is values[3] for values = [83, 61, 89, 50, 41]?
2Algorithms & logicStart with total = 37. Repeat 11 times: add 16 to total. What is the final total?
3Algorithms & logicConvert the binary number 1100000 to decimal.
4Data structuresA sorted array has 1023 entries. Binary search always inspects a middle entry. What is the largest number of inspected entries for a successful search? Round the final result to 4 decimal places if needed.
5Data structuresA sorted array has 8191 entries. Binary search always inspects a middle entry. What is the largest number of inspected entries for a successful search? Round the final result to 4 decimal places if needed.
6Data structuresA sorted array has 3 entries. Binary search always inspects a middle entry. What is the largest number of inspected entries for a successful search? Round the final result to 4 decimal places if needed.
7Data systemsA 665 MB payload is sent over a constant 140 Mbps link. Use decimal MB and ignore overhead. Find transfer time. Round the final result to 4 decimal places if needed. Answer in s.
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8Data systemsA 624 MB payload is sent over a constant 100 Mbps link. Use decimal MB and ignore overhead. Find transfer time. Round the final result to 4 decimal places if needed. Answer in s.
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9Data systemsA 791 MB payload is sent over a constant 65 Mbps link. Use decimal MB and ignore overhead. Find transfer time. Round the final result to 4 decimal places if needed. Answer in s.
s
10Digital literacyA raw image is 97 × 115 pixels with 1 bytes per pixel. Ignoring headers and compression, how many bytes?
11Digital literacyHow many bits are in 4574 bytes?
12Digital literacyAn image is 350 pixels wide and 210 pixels high. How many pixels does it contain?

From Grade 8

These questions check skills from the grade below, so gaps can be spotted early.

13Algorithms & logic (Grade 8)Which instruction represents repetition?
14Digital literacy (Grade 8)A stranger asks for your password in a game chat. What is the safest response?
15Algorithms & logic (Grade 8)What is an algorithm?