W2
Work Rate Problems
工作效率问题
Modeling / 建模Grades G5 - G8
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What It Looks Like
Recognition signals — when you see these, think of this structure:
- 1Problems about people working together
- 2Questions like 'A can do it in x hours, B in y hours'
- 3Pipes filling tanks or similar scenarios
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What It Really Tests
The core mathematical idea behind this structure:
If someone completes a job in T time, their rate is 1/T per unit time. Rates add when working together.
如果某人在T时间完成工作，其效率为每单位时间1/T。一起工作时效率相加。
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Why Students Get Stuck
Common mistakes to watch out for:
- ⚠Adding times instead of rates
- ⚠Not converting to rates first
- ⚠Forgetting to convert back to time at the end
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Your First Step
How to begin thinking about problems with this structure:
Convert each person's time to a rate (1/time), add rates if working together, then find total time.
将每人的时间转换为效率（1/时间），一起工作时效率相加，然后求总时间。
Related Structures
These structures share similar patterns or thinking approaches: