To the nearest tenth of a percent of the 7th grade students were in favor of wearing school uniforms

Samantha swam upstream for some distance in one hour. she then swam downstream the same river for the same distance in only 12 minutes. if the river flows at 4 mph, how fast can samantha swim in still water?

This is about circle theorems. someone asap : (

Awindow washer cleans 42 windows in 2 hours. at this rate, how many windows did he clean in 180 minutes.