Answer:
A: 40 degrees
Step-by-step explanation:
Since every triangle is 180 degrees, you can start off by subtracting 50 from 180 since that side does not contain a y for you to solve.
Since the other two sides do have a y in them, you would set 130 degrees equal to y+10 and 2y:
130=y+10+2y
Then you would isolate the y's by subtracting 10, and you would add y and 2y together to get:
120=3y
Finally, you would divide 120 by 3 to get your answer, 40=y.
Hope this helps!