Practice city guilds model questions vol1 information_technology 2024 Past Questions

Question 1 View Details

A company needs to divide the network $192.168.0.0/24$ into subnets for three departments requiring at least 30, 12, and 6 usable host addresses respectively. Using variable‑length subnet masks (VLSM) and allocating the largest subnet first, determine the subnet mask (in dotted‑decimal notation) for the department that needs 6 hosts and list its usable IP address range.

A. Subnet mask 255.255.255.248; usable IP range 192.168.0.57 - 192.168.0.62

B. Subnet mask 255.255.255.252; usable IP range 192.168.0.49 - 192.168.0.50

Correct C. Subnet mask 255.255.255.248; usable IP range 192.168.0.49 - 192.168.0.54

D. Subnet mask 255.255.255.240; usable IP range 192.168.0.49 - 192.168.0.62

Correct Answer: C

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 2 View Details

Consider a relation R(A,B,C,D,E) with functional dependencies: A→B, BC→D, D→E, and AB→C. Identify the highest normal form (1NF, 2NF, 3NF, BCNF) that R satisfies.

Correct A. 2NF

B. 1NF

C. 3NF

D. BCNF

Correct Answer: A

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 3 View Details

Add the two 7‑bit binary numbers $1011011_2$ and $0110101_2$ using two's‑complement arithmetic. State the 7‑bit result and indicate whether an overflow occurs.

A. 1111111, overflow

B. 0101100, no overflow

C. 0010000, overflow

Correct D. 0010000, no overflow

Correct Answer: D

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 4 View Details

A user reports that the website www.example.com cannot be opened. The following observations are made: - Ping to 8.8.8.8 succeeds. - Ping to www.example.com fails. - nslookup www.example.com returns "** server can't find www.example.com: NXDOMAIN **". - Traceroute to 8.8.8.8 reaches the destination, but traceroute to www.example.com stops at the second hop. Based on these symptoms, identify the most likely cause of the problem and the first corrective action the IT support technician should take.

A. Network connectivity issue; first action is to verify the physical cable connections

B. Firewall blocking; first action is to disable the firewall temporarily

Correct C. DNS resolution failure; first action is to check/fix the DNS server settings (e.g., use a working DNS server or flush the DNS cache).

D. Web server down; first action is to restart the web server service

Correct Answer: C

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 5 View Details

An RSA public key is (N = 2773, e = 17). A ciphertext C = 855 has been received. Given that N = p·q with p and q being prime numbers, determine the plaintext message M (as an integer) by first finding the private exponent d and then decrypting C.

A. 855

Correct B. 1029

C. 1234

D. 2048

Correct Answer: B

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 6 View Details

A spreadsheet uses the formula $=VLOOKUP(A2,\$B\$1:\$C\$4,2,TRUE)\times A2$ to calculate commission for each salesperson, where column A contains the sales amount. The lookup table in cells B1:C4 is: B1: 0 C1: 0.03 B2: 5000 C2: 0.04 B3: 10000 C3: 0.06 B4: 20000 C4: 0.08 The sales amounts entered in A2:A6 are 4200, 7500, 11000, 4800, and 9500 respectively. What is the total commission paid to the five salespeople?

Correct A. 1610

B. 1700

C. 1652

D. 1500

Correct Answer: A

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 7 View Details

Cell $B1$ contains the tax rate 0.075. Column $A$ lists amounts for four items: 1200, 2500, 1800 and 3000. In cell $C1$ the formula $=A1*\$B\$1$ is entered and copied down to $C4$. A student mistakenly used a relative reference to $B1$ (i.e., wrote $=A1*B1$) before copying, so the tax‑rate column now contains 0.075, 0.080, 0.085 and 0.090 respectively (each row increased by 0.005). The total tax is summed in $C5$ with $=SUM(C1:C4)$. What is the difference between the erroneous total tax and the correct total tax?

Correct A. 75.5

B. 75.0

C. 80.5

D. 71.5

Correct Answer: A

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 8 View Details

A month‑long sales record contains 30 days. Twenty‑four days have recorded sales (in naira) as follows: 4200, 5300, 6100, 4800, 7500, 3000, 5600, 6200, 4100, 5900, 4700, 6800, 7200, 3500, 5400, 6600, 4300, 5000, 5800, 3900, 6100, 4500, 5300, 6400. The remaining six days are blank. The manager decides to replace each blank with the average of the non‑blank entries, then count how many days have sales of at least 5000 naira. How many days meet this criterion after the blanks are filled?

A. 24

B. 20

Correct C. 21

D. 22

Correct Answer: C

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 9 View Details

A spreadsheet stores data for five products. Columns are: $B$ - Units sold, $C$ - Unit price (naira), $D$ - Profit‑margin % (as a whole number). The data are: - Product A: Units 800, Price 25, Margin 15\n- Product B: Units 1500, Price 30, Margin 12\n- Product C: Units 600, Price 45, Margin 20\n- Product D: Units 2000, Price 22, Margin 10\n- Product E: Units 400, Price 55, Margin 18 A discount of 5 % off the unit price is applied to any product whose units sold exceed 1000. Using these rules, what is the total profit (in naira) for all five products? (Profit for a product = Units $\times$ Effective price $\times$ Margin/100.)

A. 22160

B. 21890

Correct C. 21670

D. 21052

Correct Answer: C

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 10 View Details

The following 20 test scores (out of 100) were obtained by a class: 68, 75, 82, 90, 55, 77, 84, 69, 73, 88, 92, 61, 70, 78, 85, 79, 66, 81, 74, 80. Using the inclusive‑median method (median is the average of the two middle values for an even‑sized set), determine: 1. The interquartile range (IQR).\n2. The probability, expressed as a reduced fraction, that a randomly selected student scored above the mean. Provide your answer as "IQR, probability" (e.g., "13.5, 11/20").

A. 13.0, 3/5

B. 14.0, 1/2

Correct C. 13.5, 11/20

D. 12.5, 9/20

Correct Answer: C

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 11 View Details

A byte (8 bits) stores the binary pattern $01001000$. Interpreting this as an ASCII code, which character is represented?

Correct A. H

B. J

C. G

D. I

Correct Answer: A

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 12 View Details

A presenter plans a presentation lasting exactly $10$ minutes ($600$ seconds). Each slide is shown for $30$ seconds, and between consecutive slides there is a transition of $5$ seconds. Some slides contain animations that add an extra $15$ seconds each. If exactly three slides have animations, how many slides are in the presentation?

Correct A. 16

B. 18

C. 17

D. 15

Correct Answer: A

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 13 View Details

In a data set of seven test scores, six scores are known: $70, 75, 80, 90, 95, 100$. One score is missing. The overall mean of the seven scores is $85$. Moreover, after arranging the seven scores in ascending order, the median equals the average of the lowest and highest scores. Determine the missing score.

Correct A. 85

B. 75

C. 80

D. 90

Correct Answer: A

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 14 View Details

Consider the following pseudocode:\n\n``` count = 0 for i = 1 to n: for j = i to n: if (i + j) mod 3 = 0: count = count + 1 ```\n\nFor $n = 100$, how many times is the statement `count = count + 1` executed?

A. 1665

B. 1620

Correct C. 1683

D. 1700

Correct Answer: C

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 15 View Details

A presentation file consists of 20 slides. Each slide contains a background image of $2.5$ MB uncompressed. The presenter applies a compression that reduces each image size by $40\%$ and then saves the presentation in a format that adds an overhead of $5\%$ of the total compressed image size for metadata. Additionally, the text and animations together add a fixed $10$ MB to the file. What is the total file size in megabytes, rounded to two decimal places?

A. 40.00

B. 42.50

Correct C. 41.50

D. 31.00

Correct Answer: C

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 16 View Details

A computer uses an 8‑bit signed two's‑complement representation. What is the binary representation of the decimal number $-45$?

A. 11010101

B. 10010111

Correct C. 11010011

D. 11101011

Correct Answer: C

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 17 View Details

A system requires passwords of length 8 characters. The allowed character set consists of 26 lowercase letters, 26 uppercase letters, 10 digits, and 5 special symbols. The actual password chosen by a user contains exactly 2 digits, exactly 1 special symbol, and the remaining 5 characters are lowercase letters (no uppercase). Characters may repeat. An attacker attempts passwords by randomly generating strings that satisfy the same composition (i.e., exactly 2 digits, 1 special, 5 lowercase) with equal probability. What is the probability that the attacker guesses the correct password on the first try?

Correct A. 1/998035584000

B. 1/998035584001

C. 2/998035584000

D. 1/997035584000

Correct Answer: A

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 18 View Details

An IT support technician must configure the subnet mask for a LAN. The LAN must accommodate at most 50 usable host addresses per subnet. Two computers on the same subnet have IP addresses 10.0.4.22 and 10.0.4.58. Determine the subnet mask (in dotted‑decimal notation) that satisfies the host requirement and places both computers in the same subnet, and give the broadcast address for that subnet.

A. 255.255.255.0, 10.0.4.255

B. 255.255.255.224, 10.0.4.31

Correct C. 255.255.255.192, 10.0.4.63

D. 255.255.255.128, 10.0.4.127

Correct Answer: C

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 19 View Details

An intrusion‑detection system (IDS) has a detection rate of 95 % for real attacks and a false‑positive rate of 2 % (i.e., it raises an alert on 2 % of benign events). On any given day, the prior probability that an attack occurs is 0.001. If the IDS raises an alert on a particular day, what is the probability (as a percentage to two decimal places) that an actual attack is occurring?

A. 2.00%

Correct B. 4.54%

C. 5.00%

D. 0.95%

Correct Answer: B

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 20 View Details

A database contains three tables: Employees (E) with 2,000 rows, Departments (D) with 50 rows, and Projects (P) with 300 rows. Each employee belongs to exactly one department, and only 10 % of employees are assigned to a project. The join conditions are E.dept_id = D.id and E.proj_id = P.id. Considering two possible join orders—(E ⋈ D) then ⋈ P, and (E ⋈ P) then ⋈ D—estimate the size of the intermediate results for each order and state which order minimizes the size of the largest intermediate result.

Correct A. Join Employees with Projects first (E ⋈ P)

B. Join Departments with Projects first (D ⋈ P)

C. Join Employees with Departments first (E ⋈ D)

D. Join Projects with Departments first (P ⋈ D)

Correct Answer: A

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 21 View Details

A DNS resolver receives a query for the domain example.com. The resolution path involves a root server (response time 20 ms), a TLD server (30 ms) and an authoritative server (40 ms). The resolver caches the answer with a TTL of 300 seconds. The client makes five queries at times 0 s, 200 s, 310 s, 600 s and 900 s. If a cached answer is used, the lookup takes only 5 ms; otherwise the full resolution time (sum of the three server times) is incurred. Calculate the total time, in milliseconds, spent on DNS resolution for all five queries.

Correct A. 280

B. 295

C. 300

D. 260

Correct Answer: A

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 22 View Details

An organization has been allocated the IPv4 network 192.168.0.0/24. It must create sub‑networks for three departments with the following host requirements: Department A - 50 hosts, Department B - 20 hosts, Department C - 10 hosts. Using variable‑length subnet masking (VLSM) and allocating sub‑nets in order of decreasing size, determine the subnet address and mask assigned to Department B and state the first usable IP address in that subnet.

A. Subnet: 192.168.0.96/27, first usable IP: 192.168.0.97

B. Subnet: 192.168.0.64/26, first usable IP: 192.168.0.65

C. Subnet: 192.168.0.64/27, first usable IP: 192.168.0.66

Correct D. Subnet: 192.168.0.64/27, first usable IP: 192.168.0.65

Correct Answer: D

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 23 View Details

A web page consists of one HTML file of size 20 KB and four image files each of size 30 KB. The client accesses the site using HTTP/1.1 with persistent connections, but the browser may open at most two parallel connections to the same server. The round‑trip time (RTT) to the server is 120 ms and the available bandwidth is 2 Mbps. TCP segments can carry a maximum payload of 10 KB. Assuming negligible processing delay and no pipelining, compute the total time, in milliseconds, from the start of the first TCP handshake until all five objects have been received, assuming an optimal schedule of the transfers.

A. 720

B. 1080

C. 960

Correct D. 840

Correct Answer: D

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 24 View Details

A user on the corporate LAN cannot access any web sites. The observations are: • The user can ping the default gateway (192.168.1.1) in 2 ms. • The user can ping the DNS server (192.168.1.53) in 5 ms. • The user can ping the external IP address 8.8.8.8 in 20 ms. • DNS look‑ups fail; nslookup for www.google.com returns "server failed". • A packet capture on the DNS server shows incoming DNS queries from the user's IP address but no DNS replies are sent. • The DNS server's firewall has a rule allowing inbound UDP port 53 only from the subnet 192.168.1.0/24. The user's IP address is 192.168.2.10. Identify the most probable cause of the problem and state the corrective action required.

Correct A. The DNS server firewall blocks the user's subnet (192.168.2.0/24) from receiving UDP/53 replies. Fix by adding a rule to allow DNS traffic from that subnet (or place the user in the allowed subnet).

B. The firewall on the user's workstation is blocking outbound DNS queries; disable the local firewall or allow UDP/53.

C. The user's default gateway is misconfigured; update the gateway IP to 192.168.1.1.

D. The DNS server is down; restart the DNS service to restore resolution.

Correct Answer: A

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 25 View Details

Consider a relation R(A, B, C, D, E) with the functional dependencies: A → B, BC → D, D → E, E → A. (i) List all candidate keys of R. (ii) Decompose R into a collection of relations that are in Boyce‑Codd Normal Form (BCNF). Present each resulting relation by listing its attributes.

A. Candidate keys: AB, BD, AE. BCNF decomposition: R1(A,B), R2(A,D), R3(C,E), R4(D,C).

B. Candidate keys: AB, BC, DE. BCNF decomposition: R1(A,B), R2(B,D), R3(D,E), R4(E,C).

C. Candidate keys: AB, AD, AE. BCNF decomposition: R1(A,B), R2(B,C), R3(C,D), R4(D,E).

Correct D. Candidate keys: AC, CE, CD. BCNF decomposition: R1(A,B), R3(E,A), R5(D,E), R6(D,C).

Correct Answer: D

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

city guilds model questions vol1 2024 information_technology | Objective

Master the Exam!

Help others prepare! Share this practice hub: