50%
Notice how the entire line segment is split into 4 sections.
Section 1: 50 - 100
Section 2: 100 - 140
Section 3: 140 - 170
Section 4: 170 - 190
Since it's 4 sections, each section equals 25%
Here we need to find the percentage from 100 - 170
That means sections 2 - 3
Section 2 + Section 3 = 25% + 25% = 50%