Two questions in Equity solution, structure

hw0799

1. Example 19 (Reading 41, pg 427, Equity)
Given Vfirm = 17401
Capital structure = 20% Debt : 80% Equity
Long term debt - 1518
=> Vequity?

Book's solution: Vequity = Vfirm - Long term debt = 17401 - 1518=15883

Question: Why not use the Capital structure here (ie: Vequity = Vfirm* 80% = 13,920.8)? Long term debt is just a part of debt, there might be short term debt, ect

2. Example 36 (Reading 42, pg 538, Equity)
Enterprise value = Equity + Debt + Minority Interest - Cash
Why + Minority Interest and - Cash?