Question

How many pillars are needed to construct a bridge 100m long, if their are to be at a distance of 2.5 m each from one end to the other.

Answer 1

Length of bridge = 100m

Distance between each pillars = 2.5m

2.5m distance = 1 pillar

100m distance = 100 × 1 / 2.5 = 40 pillars

Therefore 40 pillars are needed to construct a bridge of 100m long.