Ketan and Kunal can complete a job together in 7 days. Kunal is $\frac{7}{4}$ times as efficient as Ketan. In how many days can Kunal alone complete the job?
Answer & explanation
Correct answer: option 4
Ketan + Kunal = 7 days,
Ketan : Kunal = 7 : 4 (Efficiency)
⇒ They both working together can complete a work in 7 days = (7+4) x 11 = 77 units, ..(Efficiency × Days = Total work)
⇒ Time required by Kunal to complete the work alone = \(\frac{77}{7}\) = 11 days, ..(\(\frac{Work}{Efficiency}\) = Time)