Answer:
Ladder is moving away from the wall with the speed of 3.464 ft/s
Explanation:
Consider the figure attached
Given that top of ladder slides down with the speed of 2ft/sec, i.e

Length of ladder =10 ft
bottom of the ladder is 5 ft from the wall i.e b=5
By pythagorous theorem

Differentiating equation (1) w.r.to t

Negative sign shows that ladder is moving away from wall