Question

Can someone explain how this equation is solved? I have it already solved but I don't understand how the outcome is got but here is the problem.

Selling price=(1+r)(original cost)
63=(1+r)(42)
1.5=1+r
r=0.5

How did we go from that first part of the problem to the second; what was done exactly?

Answer 1

First step plug in the values
Then 63/42
Then 1.5-1