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S4 ICT Cloud and IoT: Paper 4 Error Clinic
S4 ICT Cloud and IoT: Paper 4 Error Clinic
This paper gathers the most common slips from the first three papers: GB conversion, upload time and address space first, then sampling counts, scaling and two-step conversion, followed by packet totals, cost and latency ratios, and a final correction that treated a day as an hour.
Direct answers Items 01 to 03 correct capacity, time and address space, 04 to 06 handle sampling, scaling and two-step conversion, 07 to 09 cover packet volume, cost and ratios, and 10 corrects a day-for-an-hour slip.
01 Paper details (check answers afterwards)
| Item | Detail |
|---|---|
| Questions | 10 |
| Suggested time | 20 |
| Difficulty mix | Foundation 3 · Intermediate 3 · Challenge 3 · Error redo 1 |
| Chapter | Chapter: S4 ICT Cloud Computing and IoT |
| Level | S4 |
02 Questions (10 items)
- FoundationA student wrote 3 GB = 3000 MB. What went wrong, and what is the correct value in MB with 1 GB = 1024 MB?
- FoundationA student said a 60 MB file at 10 MB per second takes 600 seconds. What went wrong, and what is correct?
- FoundationA student wrote that a 32-bit IPv4 address space holds 2 times 32, or 64, addresses. What went wrong?
- IntermediateA sensor samples every 12 seconds. A student answered 5 readings per hour. What went wrong, and what is correct?
- IntermediateA student said a 250 MB backup at 5 MB per second takes 1250 seconds. What went wrong, and what is correct?
- IntermediateA student wrote 1 TB = 1000 GB = 1,000,000 MB. What went wrong, and what is the correct value in MB?
- ChallengeThirty devices each send one packet every 10 seconds. A student answered 43,200 packets a day. What went wrong?
- ChallengeCloud storage costs $0.25 per GB per month and 500 GB is used. A student answered $2000. What went wrong?
- ChallengeThe same task takes 4 ms locally and 60 ms in the cloud. A student said the cloud is 56 times slower. What went wrong?
- Error redoA thousand devices each send 6 packets per minute. A student answered 360,000 packets a day. What went wrong?
03 Answers and one-line notes
| # | Answer | One-line note |
|---|---|---|
| 1 | He used 1 GB = 1000 MB; the correct value is 3072 MB, which is 72 MB more | Binary storage steps by 1024, so 3 times 1024 gives 3072 MB, which is 72 MB above 3000. |
| 2 | He multiplied instead of dividing; 60 divided by 10 gives 6 seconds | Time equals size divided by speed, and multiplying inflates the answer a hundred times. |
| 3 | He treated a power as a product; the space holds 2 to the power 32, which is 4,294,967,296 | Each bit doubles the count, so 32 bits multiply by two thirty-two times, not by thirty-two. |
| 4 | He divided 60 by 12 and stopped; one hour is 3600 seconds, so 3600 divided by 12 gives 300 readings | An hour holds 3600 seconds, so a single division gives 300 and 5 comes from using only 60 seconds. |
| 5 | He multiplied size by speed; 250 divided by 5 gives 50 seconds | Upload time is size over speed, and multiplying gives an answer 25 times too large. |
| 6 | He stepped by 1000; 1 TB is 1024 GB, which is 1,048,576 MB | Both steps use 1024, and 1024 times 1024 gives 1,048,576, which is 48,576 MB above a million. |
| 7 | He counted one packet per minute; a day gives 86400 divided by 10, which is 8640, and times 30 makes 259,200 | Six packets a minute means 8640 a day per device, so thirty devices give 259,200, six times his answer. |
| 8 | He divided by the unit price; 500 times 0.25 gives $125 | Cost is capacity times unit price, and dividing by the price inflates the figure sixteen times. |
| 9 | He read the 56 ms gap as a ratio; 60 divided by 4 gives 15 times | Ratios need division, and subtracting only gives a 56 ms gap, which means something else. |
| 10 | He multiplied by 60 minutes, treating a day as an hour; the correct total is 1000 times 6 times 1440, or 8,640,000 | A day holds 1440 minutes, and missing that factor of 24 leaves him 8,280,000 packets short. |
04 What to do after marking
- After marking, redo only the wrong items and write down which step went wrong (formula, unit, or misread number).
- Repeat the same item two days later; move to the next paper only when both attempts are correct.
- Parents only need the answer and note columns; there is no need to explain every item.
S4 ICT cloud and IoT paper 4: ten error-clinic items on binary conversion, upload time, address space, packet volume and latency ratios.Tutor Registration →
Questions and answers are written originally by the TutorZone team and are not taken from any school, publisher or examination authority paper. Every value is checked by computer.