Jens motorboat travels at a speed of 15mph in still water, the river flows at a speed of 2pmh, how long will it take jen to travel 20mi upstream? 20mi downstream?

The speed of the motorboat travelling up stream will be 13mph, therefore it will take 20/13 hours to travel 20 miles upstream. This is about 1 and a half hours. The speed of the motorboat travelling downstream will be 17mph, therefore it will take 20/17 hours to travel 20 miles downstream. This is about 1 hour 10 minutes.

I'm pretty sure it's b). i try drawing the functions out and b is the one that stands out or isnt a "line"