The angle between an incident ray and the mirror is 30º:

Thx Lance :)

Can you plz explain HOW you got the answer. 

Don't take those two seriously. They are a bunch of pranksters. You should direct your physics questions to "Alan" one of the moderators here, since he is very good at answering physics questions.

Hi Eloise

I know how to do this one.

Remember for a regular mirror the angle of incidents is equal to the angle of reflection.

Remember that 90 degrees is going directly into the mirror and 0 degrees is going across the surface and not reflect at all.

 The angle between an incident ray and the mirror is 30 degrees.  

subtract the 30 from the 90

90 – 30 = 60 degrees

The ray reflects at the same angle of 60 degrees

So the total angle is 120 degrees

This picture should help:

Note that the angle through which the ray turns is 180° - 60° - 60° = 60°

Thx Alan