問55
頻出度★★★
ソフトウェア開発の仕事に対し，10名が15日間で完了する計画を立てた。しかし，仕事開始日から5日間は，8名しか要員を確保できないことが分かった。計画どおり15日間で仕事を完了させるためには，6日目以降は何名の要員が必要か。ここで，各要員の生産性は同じものとする。
令和5年度 ITパスポート試験 問55
マネジメント系プロジェクトマネジメント › プロジェクトマネジメント
This question's explanation and your answers so far.
解説
問 55
Incorrectア
10 is simply the number of people in the original plan; it does not account for adding people to make up for the delay (a shortfall of 10 person-days) caused by the drop to 8 people during the first 5 days. With only 10 people, 110 person-days cannot be finished in 10 days, so the work falls behind the plan.
- イ
正解 Treat the total workload in terms of person-days (number of people × number of days). The original plan is 10 people × 15 days = 150 person-days. During the first 5 days only 8 people are available, so only 8 people × 5 days = 40 person-days of work is done, leaving 150 − 40 = 110 person-days remaining. The remaining number of days is 15 − 5 = 10 days, so the number of people needed from the 6th day onward is 110 person-days ÷ 10 days = 11 people. Therefore, choice イ is correct.
Incorrectウ
With 12 people, the remaining 10 days give 12 × 10 = 120 person-days, which exceeds the required 110 person-days by 10 person-days — too many. This results from not correctly computing the remaining work as 110 person-days, or from overestimating the shortfall.
Incorrectエ
With 14 people, the remaining 10 days give 14 × 10 = 140 person-days, far exceeding the 110 person-days. This value comes from subtracting from the total of 150 person-days not the 40 person-days already completed but the 10 person-day shortfall of the first 5 days, giving a remaining workload of 140 person-days (140 ÷ 10 days = 14 people).
ここがポイント
- The key idea is to treat the workload as constant in person-days (number of people × number of days), and to find the remaining work as total − already consumed = remaining work.
- Calculate the required number of people as remaining workload (person-days) ÷ remaining days (days) (110 person-days ÷ 10 days = 11 people).
用語