Answer:
130°
Step-by-step explanation:
The diagram for the question is redrawn on the attached image. It was obtained online.
Basically, what the question is asking is for the angle between the new path of the beam and the old path if the beam continued without being reflected by the mirror.
The line of the old path of the beam of light is a straight line. And the sum of angles on straight line = 180°
25° + 25° + y° = 180°
y = 180° - 50° = 130°
