State whether 25 prime, composite or neither

Akayaker travels 3 miles upstream and 3 miles downstream in a total of 4 hours. in still water, the kayaker travels at a speed of 2 mph. what is the average speed of the river's current?

Naruto is choosing between two venues that will deliver food to his house. with probability 1/3 he will choose ramen mania (r), and with probability 2/3 he will choose sushi (s). if he chooses r, 15 minutes after making the call, the remaining time it takes the food to arrive is exponentially distributed with average 10 minutes. if he orders s, 10 minutes after making the call, the time it takes the food to arrive is exponentially distributed with an average of 12 minutes. given that he has already waited 25 minutes after calling, and the food has not arrived, what is the probability that he ordered from r? i am really stuck on how to set this up, so if you could be extra clear, that would be super ! in advance

How many points must you create to draw a line a segment or a ray