Need the ratio in the simplest form

If the sales price of a dvd is $20 and the markup is 34%, what is the cost of the dvd?

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?

Carlos by 24 mi and ran 6 miles what is the ratio of the distance carlos ran to the distance he biked