Question

A 25 foot ladder is placed against a vertical wall.The foot of the ladder is 7 feet from the base of the building.If the top of the ladder slips 4 feet, then the foot of ladder will slide by ?​

Answer 1

the following picture explains :

the answer comes 15 foot....that is

the foot slips by =15-7=8foot

Answer 2

4feet cause the ladder slipped 4 feet from the building. there fore it is understood that it will slip 4 feet only (just kidding) 15 feet is the answer!