A and B together can finish a job in 40 days. A can do the same job on her own in 60 days. How long will B take to do the three-fourth of the same work all alone?
Answer & explanation
Correct answer: option 1
A + B = 40 days,
A = 60 days,
⇒ A + B = 3 (Efficiency)
⇒ 2 + B = 3
⇒ B = 1,
⇒ \(\frac{3}{4}\)th of total work = \(\frac{3}{4}\) x 120 = 90 units,
⇒ Time taken by B to complete 90 units of work = \(\frac{90}{1}\) = 90 days. ..(\(\frac{Work}{Efficiency}\) = Time)