IPA IP 2026 Question 50
A question IPA Japan published in 令和8年度 ITパスポート試験 公開問題 問50, translated into English. ITPEC is based on the same exams.
When the activities in the following table are performed by 3 persons, what is the minimum number of days required to complete all activities? Here, an activity that requires multiple staff cannot be started until all of them are available, and assigning more staff than the specified number does not shorten the days required. Also, an activity that has been started cannot be interrupted until it is completed.
Explanation
15 days — with only 3 persons, the two 2-person activities B and C cannot run at the same time, which adds 3 days to the 12-day critical path.
Every path is 12 days long (A→B→D→F and A→C→E→F), but B, C and E each need 2 persons, so no two of them can run together. The best schedule pairs a 1-person activity with a 2-person one:
Starting C before B gives the same 15 days at best (C, then B, then E with D). A search of every possible schedule confirms that none finishes sooner.
Answer (c)
Why not others:
- •(b) 12 days — the critical path with unlimited staff; it needs B and C (4 persons) at the same time
- •(a) 9 days — shorter than any chain of dependent activities, which is 12 days
- •(d) 18 days — doing all six activities one after another, missing that D (1 person) can run beside C (2 persons)
Key rule: With limited staff, the shortest schedule is set by both the dependencies and the staff available on each day: check which activities can share the staff limit, not only the critical path.
Project Management · AI-written, may contain errors
This question comes from the past questions IPA Japan publishes, translated into English by ITPEC Practice. ITPEC Practice is an independent study tool and is not affiliated with IPA or ITPEC. See the original paper (PDF) or Report an issue.