Kim is reading a book with 380 pages. She read 20 pages each day until she reached Part 2 of the book. Part 2 of the book is 160 pages long. She uses the equation 380−20=160 380 - 20 d = 160 to represent the number of days, d, it took her to read Part 1. How many days did it take Kim to read Part 1 of the book?