Step-by-step explanation:
Let drain A nad be are used to empty a swimming pool.
Given drain A alone can empty the pool in 4.75 hours.
When both A and B are open, it takes 2.6 hours.
The time taken by B to draint the pool = ?
[tex]\frac{t+4.75}{4.75t} = \frac{1}{2.6}[/tex]
2.6 (t+4.75) = 4.75t
2.6t + 12.35 = 4.75t
t = 5.744 hours
It takes 5.744 hours for drain B to empty the pool.