Opposite angles have equal measures.

Since $\angle A O C$ and $\angle D O B$ are opposite angles, then $y=40$.

Straight angle $C O D$ measures $180^{\circ}$.

Since $\angle A O C+\angle A O D=\angle C O D$, then $40^{\circ}+x^{\circ}=180^{\circ}$ and so $x=140$.

The difference $x-y$ is $140-40=100$.

![](https://cdn.mathpix.com/cropped/2024_04_20_748fdafcde2a47412608g-196.jpg?height=217&width=421&top_left_y=192&top_left_x=1470)

ANSWER: (E)
If two straight lines intersect as shown, then $x-y$ is
(A) 0
(B) 40
(C) 80
(D) 60
(E) 100

![](https://cdn.mathpix.com/cropped/2024_04_20_6027bc27089ed4fc493cg-040.jpg?height=192&width=379&top_left_y=495&top_left_x=1339)