SRSS Sec 4 COMP PRELIM 2022 PAPER 1

This question paper consists of 14 printed pages including the cover page. [Turn over SERANGOON SECONDARY SCHOOL PRELIMINARY EXAMINATION SECONDARY 4 EXPRESS CANDIDATE NAME CLASS CENTRE NUMBER S INDEX NUMBER COMPUTING 7155/01 Paper 1 25 August 2022 2 hours Setter(s): Mr Adrial Tan READ THESE INSTRUCTIONS FIRST Write you Centre number, index number and name in the spaces at the top of this page. Write in dark blue or black pen. You may use an HB pencil for any diagrams, graphs or rough working. Do not use staples, paper clips, glue or correction fluid. Approved calculators are allowed. Answer all questions. The number of marks is given in brackets [ ] at the end of each question or part question. You should show all your working. The total number of marks for this paper is 80. For Examiner’s Use 80

2 1 Anthony uses a spreadsheet to record his expenses. He records: • the date of purchase and the amount spent on each item • the mode of payment of each item purchased (cash or credit card) A B C D E 1 Date Item Amount ($) Payment mode (cash/credit card) 2 01/07/2022 EZ link card top up $ 50.00 credit card 3 08/07/2022 Clothing $ 120.00 cash 4 15/07/2022 Books $ 45.00 cash 5 17/07/2022 Movie $ 10.00 credit card 6 25/07/2022 Phone Bill $ 45.00 credit card 7 8 Cash expenses: $ 165.00 9 Credit card expenses: 10 Total expenses: (a) Identify the most appropriate data type for the data in the following cell references: Cell Data type A1 A3 C6 D4 (b) The cell C10 will calculate the total expenses. Identify the function that will need to be entered into C10. …………………………………………………………………………………………….. [1] (c) The cell C9 will calculate the total expenses that he had paid using credit card. Anthony uses one function to calculate this value. Describe the formula that will need to be entered in cell C9. ………………………………………………………………………………………………… ………………………………………………………………………………………………… ………………………………………………………………………………………………… ………………………………………………………………………………………………… …………………………………………………………………………………………….. [3] [4]

3 2 Anthony wants to make sure his computer is secure against cyberattacks. (a) Some of the following words need to be used to complete the description of cyberattacks. cookies data hardware harmless internet LAN pharming phishing software spamming spyware Trojan-horse reputable restricted worm Insert five words from the list given to complete the following statements. A cyberattack is an unwelcomed attempt to steal, expose, alter, disable or destroy information through unauthorised access to computer systems. It is usually carried out over a network such as the ……………………………………… . One type of cyberattack is ……………………………………… . This is a type of malware that downloads onto a computer disguised as a ……………………………………… program and attacks a computer by enabling intruders to open backdoors for unauthorised access to the computer. A second type of cyberattack is ……………………………………… . This is a form of social engineering attack which sends fraudulent communications that appear to come from ……………………………………… sources in order to steal personal information such as passwords and credit card numbers from users. [5]

4 (b) Anthony wants to protect his data from accidental damage and malicious actions. The table has three problems that can cause damage to data. Complete the table by describing the effect of each problem. Give one preventive measure for keeping data safe for each problem. Each effect and preventive measure must be different for each problem. Problem Effect Preventive measure Power failure …………………………………… …………………………………… …………………………………… …………………………………… …………………………………… …………………………………… …………………………………… …………………………………… …………………………………… …………………………………… Human error …………………………………… …………………………………… …………………………………… …………………………………… …………………………………… …………………………………… …………………………………… …………………………………… …………………………………… …………………………………… Hardware failure …………………………………… …………………………………… …………………………………… …………………………………… …………………………………… …………………………………… …………………………………… …………………………………… …………………………………… …………………………………… [6]

5 3 Five spreadsheet functions are on the left, and six descriptions on the right. Draw one line to link each function to its correct description. Function Description [5] COUNT COUNTA COUNTIF LARGE MAX Counts the number of cells in a range that contain numbers, currencies, dates, times and percentages Counts the number of cells in a range that are not empty Counts the number of cells in a range that meet a given condition Finds a numeric value based on its position in a list when sorted by value in descending order Finds the largest numeric value in a given range of cells Rounds a number up to the nearest level of significance

6 4 Belinda is setting up a home network. There are two desktop computers and a laser printer that use a wired connection. There are five wireless devices: one laptop, one tablet, two mobile phones and one smart television. (a) The home network has a router, but does not have a switch. (i) A router and a switch are examples of network hardware. Name one feature that is the same in both a router and a switch, and one difference. Feature that is the same ……………………………………………………………….. ……………………………………………………………………………………………. Difference ……………………………………………………………………………….. ……………………………………………………………………………………………. [2] (ii) Identify and describe the function of two other network devices that could be part of the home network. Device 1 …………………………………………………………………………………. Function …………………………………………………………………………………. ……………………………………………………………………………………………. Device 2 …………………………………………………………………………………. Function …………………………………………………………………………………. ……………………………………………………………………………………………. [4] (b) Is Belinda’s home network a LAN or a WAN? Give reasons for your choice. Belinda’s home network is a ………………………………… Reasons ………………………………………………………………………………………………… ………………………………………………………………………………………………… ………………………………………………………………………………………………… [3]

7 5 (a) Three truth tables are shown State whether each truth table is correct or incorrect. Write the correct solution for any incorrect truth table. Truth table Correct or incorrect Correct solution (where needed) A B A AND B 0 0 0 0 1 1 1 0 1 1 1 1 A B A AND B 0 0 0 1 1 0 1 1 A B A NAND B 0 0 1 0 1 1 1 0 1 1 1 0 A B A NAND B 0 0 0 1 1 0 1 1 A B A NOR B 0 0 0 0 1 0 1 0 0 1 1 1 A B A NOR B 0 0 0 1 1 0 1 1 [3]

8 (b) Draw the logic circuit to represent the following Boolean statement. Do not simplify the statement. X = (A NOR B) NAND (B OR NOT C) A B X C [4] (c) Complete the truth table for the Boolean statement: X = (A NOR B) NAND (B OR NOT C) A B C Working space X 0 0 0 0 0 1 0 1 0 0 1 1 1 0 0 1 0 1 1 1 0 1 1 1 [4]

9 6 Caleb is developing an application for a new mobile game. (a) The following table shows the five stages of program development: Letter Description A Gather requirements B Implement and deploy code C Plan solutions D Write code E Test and refine code Complete the following sequence by writing one of the letters A, B, C or D (from the table above) for each stage to show the most appropriate order of each stage of program development. Note: Stage 4 has already been completed. Stage Letter 1 2 3 4 E 5 [3] (b) Caleb plans the solution using decomposition. Describe what is meant by decomposition. ………………………………………………………………………………………………….. ………………………………………………………………………………………………….. ………………………………………………………………………………………………