Answer:
H = 20.5 hours
I = 19.5 Hours
Step-by-step explanation:
Start by creating a system.
I = time which the inlet pipe takes alone to fill the pond
H = time which the hose takes alone to fill the pond
10/I + 10/H = 10
H - I = 1
H = 20.5 hours
I = 19.5 Hours