An Algebra Beginner’s problem

Healesville and Werribee are on opposite sides of Melbourne. Let’s assume you have to travel through Melbourne to get from Healesville to Werribee.

The distance from Melbourne to Healesville is approximately 60Km,

so we say H=60Km

The distance from Healesville to Werribee is approximately 90Km,

so we say L=90Km

The distance from Werribee to Melbourne is called W

Only one of the statements below is true. Which one is it?

(all units are Km)

a) W = H + L, so W = 60 + 90

b) W + L = H, so W + 90 = 60

c) W + H = L, so W + 60 = 90

d) W + H = L -H, so W + 60 = 90 – 60