Correct option is B
Given:
Pipe A can fill the tank in 5 hours.
Pipe B can empty the tank in 12 hours.
Formula Used:
Rate of work =
Time taken =
Solution:
Rate of work of Pipe A (since it fills the tank in 5 hours)
Rate of work of Pipe B = (since it empties the tank in 12 hours)
Net rate of work =
Net rate of work =
Now, time taken to fill the tank hours
Alternate Method:

Time taken to fill the tank = hours