The total length of the line is 10.
The line is divided by 2 equations. Add the two equations together to equal the total length:
x + 1 + 2x -15 = 10
Combine like terms:
3x -14 = 10
Add 14 to both sides:
3x = 24
Divide both sides by 3:
x = 24/3
x = 8
The answer is B. 8