Plz help I am confusion

Asource of laser light sends rays ab and ac toward two opposite walls of a hall. the light rays strike the walls at points b and c, as shown below: what is the distance between the walls?

Which aspect of electronic commerce does the ftc regulate? a. encryption and transfer of data b. disposing of credit reports c. network security d. antivirus software updates

Atotal of 505 tickets were sold for a school play they were either adult tickets or student tickets they were 55 more student tickets so than adult tickets how many adult tickets were sold ?