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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 3 of 5

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

1Algorithms & logicAn outer loop runs 18 times. Each time, an inner loop prints once on each of 17 iterations. How many prints occur?
2Algorithms & logicConvert the binary number 100111100 to decimal.
3Algorithms & logicFOR i FROM 4 TO 144 INCLUSIVE STEP 5: print i. How many numbers are printed?
4Data structuresA sorted array has 15 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 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.
6Data structuresA sorted array has 131071 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 12 MB payload is sent over a constant 50 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
8Data systemsA 212 MB payload is sent over a constant 150 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
9Data systemsA 791 MB payload is sent over a constant 60 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 literacyAn image is 180 pixels wide and 300 pixels high. How many pixels does it contain?
11Digital literacyA file shrinks from 1520 KB to 1064 KB. What percentage of its original size was saved?
%
12Digital literacyHow many bits are in 1779 bytes?

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)Which device is primarily used to type text into a computer?
15Algorithms & logic (Grade 8)What is an algorithm?