Ten people working 6 hours per day can complete a task in 8 days. How many…
2026
Ten people working 6 hours per day can complete a task in 8 days. How many people are needed to complete the same task in 4 days if they work 8 hours per day?
Answer: A. 15 — ConceptFor a fixed task, total work is measured in person-hours: number of people × hours worked per day × number of days. When the task is unchanged, the…
- A.
15
- B.
10
- C.
18
- D.
5
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Show answer & explanation
Correct answer: A
Concept
For a fixed task, total work is measured in person-hours: number of people × hours worked per day × number of days.
When the task is unchanged, the total person-hours remain constant; changes in daily hours or days must be balanced by the number of people.
Application
The original team performs 10 × 6 × 8 = 480 person-hours of work.
In the new schedule, each person works 8 × 4 = 32 hours in total.
Let p be the required number of people. Then p × 32 = 480, so p = 480 ÷ 32 = 15.
Cross-check
With 15 people, the available work is 15 × 8 × 4 = 480 person-hours, exactly equal to the original workload. Therefore, 15 people are needed.