A is twice as efficient as B, A takes 30 days less than B to complete a work. If they work together, in how many days, will the work be completed?
Answer & explanation
Correct answer: option 2
Time taken ∝ \(\frac{1}{efficiency}\)
A : B
ratio of efficiency 2 : 1
time taken 1 : 2 ⇒ difference R = 30
say, total work = 60
Efficiency of A & B together = 3
Time taken by A and B = \(\frac{Total\; work}{Efficiency}\)
= \(\frac{60}{3}\) = 20 days