How much arms are to gather if there is three octopi and octopi have eight legs

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?

Lisa has three classes that each last 50 minutes. what is the total number of minutes of the three classes

In a column proof the right column states your reasons