Sonu and Monu together can do a piece of work in 30 days. If Sonu is 20% less efficient than Monu, in how many days can Sonu, working alone, complete 40% of the work?
Show answer & explanation
Correct answer: D
Explanation
Given:
Sonu and Monu work together = 30 days
Sonu is 20% less efficient than Monu
To find: In how many days will Sonu alone complete 40% of the work?
Let Monu's efficiency = 100
Sonu's efficiency = 80
Ratio = Sonu : Monu = 4 : 5
Sonu + Monu = 9 parts
Combined rate of both = 1/30
Sonu's rate = (4/9) × (1/30) = 2/135
40% work = 2/5
Time = (2/5) ÷ (2/135) = 27 days