Question
Download Solution PDFTwo persons A and B working separately can sanitise a building in 6 and 10 hours, respectively. They work in stretches of one hour alternately. If A begins at 8 a.m., when will the work be finished?
Answer (Detailed Solution Below)
Detailed Solution
Download Solution PDFGiven:
Person A can sanitize a building = 6 h
Person B can sanitize a building = 10 h
Concept used:
Efficiency × Time = Total work
Calculation:
| Efficiency | Person | Time | Total work |
| 5 | A | 6 | 30 |
| 3 | B | 10 |
Now, according to the question:
⇒ (5 + 3) = 8 units = 2 hours
⇒ 2 hours = 8 units
so
⇒ 6 hours = 8 × 3 = 24 units
till 7th hours, work completed = 24 + 5 = 29 units
Remaining work = 30 - 29 = 1 unit
1 unit of work is completed by B in 1/3 hour.
Total time is taken to complete the total work = 7
∴ The correct answer is 7
Last updated on Jul 12, 2025
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