A pump can fill a tank with water in 1 hour. Because of a leak, it took $1\frac{1}{3}$hours to fill the tank. In how many hours can the leak alone drain all the water of the tank when it is full?
Answer & explanation
Correct answer: option 4
A = 1 hour, A + B = \( {1 }_{3 }^{ 1} \) hrs,
⇒ A + B = 3, (Efficiency)
⇒ 4 + B = 3,
⇒ B = -1,
Time taken by B to completely empty the cistern alone = \(\frac{4}{1}\) = 4 hrs.