The Base of a 25-Ft Ladder Leaning Against a Wall

Short Answer

The base of a 25-ft ladder leaning against a wall begins to slide away from the wall. At the instant of time when the base is 24 ft from the wall, the base is moving at the rate of 7 ft/sec. How fast is the top of the ladder sliding down the wall at that instant of time?
Round the answer to the nearest tenth, if necessary.
__________ ft/sec