TAMPEM INC (DEC 2016 ADAPTED)

it seems hat 50% debt and 50% equity are the debt and equity portion which refects the gearing of the company. Therefore this percentage are used to calculate the discount rate.

I know that question have never used the 60% equity and 40% debt percentage rate. May i know when will we use this rate ? ( I know we won’t use in this question but i’m quite curious when we will use this rate)