A tank can be filled in 10 hours. After a leak in its bottom, it takes 12 hours to fill the tank. Find the time taken by the leak to empty the full tank?

60 hours

The following chart has to be made first:

Efficiency without leak = 6

Efficiency of leakage = -1

Efficiency after leak = 6 - 1 = 5

Thus, it takes 60 hours for a tank to get emptied: \(\frac{ 60}{1 }\) = 60 hours