Jens motorboat travels at a speed of 40 miles in stillwater booth river flows at a speed of 4 mph how long will it take jen to travel 10 miles upstream and 10 miles downstream

Recall your d = rt, distance = rate * time.

bearing in mind that, when she's going downstream, she's not going 40 mph, she's going 40 + 4 mph, because the stream is adding its speed to it.

likewise, when she's going upstream, she's going 40 - 4 mph, because the stream is eroding speed from it, thus



so, "u" is 16 minutes and 40 seconds.

and "d" is 13 minutes and about 38 seconds.