Answer:
Hey there!
First, I converted 8 feet to inches. I knew that 12 inches were in a foot, so 96 inches are in 8 feet. If the water rises at 8 inches per hour, at the end of 6 hours, the water will rise 48 inches. Finally, subtracting 48 from 96, we get that there are 48 inches of rope above the water's surface.
Let me know if this helps :)