Ramesh and Ganesh can together complete a work in days. After seven days of working together, Ramesh got sick and his efficiency fell by . As a result, they completed the work in days instead of days. If Ganesh had worked alone after Ramesh got sick, in how many days would he have completed the remaining work?
Ramesh and Ganesh can together complete a work in days. After seven days of working together, Ramesh got sick and his efficiency fell by . As a result, they completed the work in days instead of days. If Ganesh had worked alone after Ramesh got sick, in how many days would he have completed the remaining work?
Solution
We define:
R = Ramesh's normal efficiency (units of work per day)
G = Ganesh's efficiency (units of work per day)
If they complete the work together in 16 days, the total work = units
Phase 1 (First 7 days): Work done =
Phase 2 (Next 10 days): Work done =
Note: because Ramesh's efficiency dropped by 30%, so he works at 70% = 0.7 of his original rate
Total work equation:
Expanding the left side:
This means Ganesh is twice as efficient as Ramesh.
After 7 days of normal work together:
Work completed =
Remaining work =
Since , we can write unit/day and units/day
Remaining work = units
If Ganesh works at 2 units/day:
Time = days
Answer: 13.5 days
Ganesh is the more efficient worker (twice as fast as Ramesh), so it's reasonable that he can handle the remaining work in a reasonable timeframe.
Key takeaway for future problems: In work problems, we always set up equations based on the fact that total work remains constant, regardless of how it's distributed over time or between workers.