A alone can do \(\frac{2}{3}\) of a work in 20 days. B is 20% more efficient than A. C alone can do the same work in 5 days less than B. D is 20% less efficient than C. If they all work together, then the work will be completed in how many days ?
Answer & explanation
Correct answer: option 2
Total time of A = 20 x \(\frac{3}{2}\)= 30 days
According to question,
A : B
Efficiency 5 : 6
Time 6 : 5
we know , 6R = 30 days So 5R = 25 days i.e. B takes 25 days
Time taken by C = 25 - 5 = 20 days
C : D
Efficiency 5 : 4
Time 4 : 5
As , 4R = 20 days
1R = 5 days . So 5R = 25 days
Total time taken by all of them together = \(\frac{300}{49}\) days