Kavita can complete a piece of work alone in 12 hours, while Komal can complete the same work alone in 18 hours. Kavita works alone for the first 4 hours and leaves. After that, Komal comes and completes the remaining work by herself. How much time did Komal take to finish the remaining work?

12 hours

Kavita = 12 hrs, Komal = 18 hrs,

⇒ Kavita worked for 4 hrs and left = 3 x 4 = 12 units,  ..(Efficiency × Days = Total work)

⇒ Remaining work = 36 - 12 = 24 units,

⇒ Time required by Komal to complete the remaining work alone = \(\frac{24}{2}\) = 12 hrs,  ..(\(\frac{Work}{Efficiency}\) = Time)