EDPT Logical Deduction Puzzles 5 — Questions and Answers
Question 1: A process scheduler uses this rule: if a job has waited more than 5 seconds, it jumps to the front. Job A waited 3 s, Job B waited 6 s, Job C waited 2 s, Job D waited 7 s. In what order do they run?
- A, B, C, D
- B, D, A, C
- D, B, A, C (Correct answer)
- B, C, D, A
Correct answer: D, B, A, C
Jobs B and D have waited over 5 s and jump to front; D > B by wait time, giving order D, B, then remaining A, C by arrival.
Question 2: If all routers are network devices, and all network devices require an IP address, then:
- All network devices are routers
- All routers require an IP address (Correct answer)
- Some routers do not need IP addresses
- IP addresses are only for routers
Correct answer: All routers require an IP address
By transitive syllogism, all routers are network devices that require an IP address.
Question 3: A cipher shifts each letter by 3 positions forward (A→D, B→E, …). What does 'ORGH' decode to?
- LOVE (Correct answer)
- LIKE
- LATE
- LODE
Correct answer: LOVE
Shifting O, R, G, H back by 3 gives L, O, V, E → LOVE.
Question 4: A database log shows: every DELETE operation is preceded by a LOCK. A LOCK was never issued today. What can you conclude?
- No data was deleted today (Correct answer)
- Data was deleted without a LOCK
- A LOCK may have been issued
- The log is incorrect
Correct answer: No data was deleted today
Contrapositive: no LOCK means no DELETE, so no data was deleted today.
Question 5: There are 5 nodes in a network ring. Messages travel clockwise. A message starts at Node 1 and must reach Node 4. How many hops does it take?
- 2
- 3 (Correct answer)
- 4
- 1
Correct answer: 3
Clockwise from Node 1: hop 1→2, hop 2→3, hop 3→4 = 3 hops.
Question 6: Statement: 'If the disk is full, writes fail.' The disk is not full. What can you conclude?
- Writes will fail
- Writes will not fail
- Nothing certain about writes (Correct answer)
- The disk will become full
Correct answer: Nothing certain about writes
Denying the antecedent (disk not full) is a logical fallacy; writes may still fail for other reasons.
Question 7: A sorting algorithm compares adjacent elements and swaps if out of order, repeating until no swaps occur. After the first complete pass over 5 elements, which element is guaranteed to be in its final sorted position?
- The smallest element
- The largest element (Correct answer)
- The middle element
- The first element
Correct answer: The largest element
Bubble sort's first pass 'bubbles' the largest element to the last position.
EDPT Logical Deduction Puzzles 5
A process scheduler uses this rule: if a job has waited more than 5 seconds, it jumps to the front.
Job A waited 3 s, Job B waited 6 s, Job C waited 2 s, Job D waited 7 s.
In what order do they run?