Answer:
wow let me try
Step-by-step explanation:it is a 90% sure
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.
Hopes this helps:
Answer: 65
Please mark as brainlist if it’s right.
Have a great day.
Let x be the total number of students.
The total of red + blue = x/4 + x/8
The remaining will be : x - x/4 -x/8
But we know the green at 3/5 of the remaining, so the green = 3/5(x - x/4 -x/8)
We also know that 3/5(x - x/4 -x/8) = 15
Solve this equation: and you will find x = 40 (number of students)