How far poles apart?

A cable, 16 meters in length, hangs between two pillars that are both 15 meters high. The ends of the cable are attached to the tops of the pillars. At its lowest point, the cable hangs 7 meters above the ground. How far are the two pillars apart?

Answer:

Zero meters apart. Since the lowest point is 7 metres from the ground, the distance of the lowest point from the top of the pillar is 8 metres which is half of 16 metre (lenth of cable). So cable should be in folded position. So distance between the pillars is 0 meters.