What is the answer to this question

First we need to understand that the sum of adjacent angles on a straight line is 180°,meaning that when all the angles are added up the answer would be 180°

Here's how we can set up the equation:

2x+100°=180°
2x=80°
x=40°

Thus the answer is 40°

Again,hope it helps!

The method to find the female dormitory is 2-d=800