Correct option is D
Given:
John's efficiency is 40% of Jesse's efficiency.
John alone can complete the work in 35 days.
Concept Used:
Efficiency is inversely proportional to the time taken to complete the work.
Solution:
Let Jesse's efficiency be E . Then, John's efficiency is 0.4E .
Let the total work be W .
John’s work rate=35Wper day
Jesse’s work rate=35W×0.41=14Wper day
Combined work rate=35W+14W=702W+5W=707W=10Wper day
Time=Combined work rateW=10WW=10days
Alternative Method:
John's efficiency is 40% of Jesse's efficiency.
John=Jesse×10040
JesseJohn=52
Total work = 2×35=70 unit
The complete the whole work together = 2+570=10