I'm sorry I'm too lazy to read all of that. However, I did get the main point. The river was going at 3 mph. Since he wanted to travel 10 miles upstream and downstream, you would have to subtract 20 by 3. This would mean he was going at a speed of 17 mph.
It is A 2827cm
This is the answer your welcome
In this question, the thing that needs to be found is the number whose 20% would be 18. The information's required for getting to the solution are already provided in the question. based on those given information's, the answer can be deduced very easily.
Let us assume the unknown number to be = x
Then
(20/100) * x = 18
x/5 = 18
x = 18 * 5
= 90
so the unknown number in the question is 90. I hope the procedure is clear enough for you to understand.
Answer:

Step-by-step explanation:
Given:

Required:
f(g(x))=?
Solution:
let f(g(x))=f(X), where X=g(x)
so 
put X=
, we get


Answer:
B. logarithms of negative number don't exist