Is the relation is a function, explain. {(8, 5), (7, 4), (6, 4), (5, 5)}

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?

Ineed with question three. i don't understand how i'm supposed to achieve 3 marks.

What is the probability that a person's favorite season is fall? write the probability as a fraction. spring - 13% summer - 39% fall - 25% winter - 13% none, i like them all - 10%