D) because the first equation*3-the second equation*;
the left side=0, the right side = 36
The answer is (3,4) since x=3 and when the line is at x=3, it hits y=4. So the answer is (3,4).
We can set it up like this, where <em>s </em>is the speed of the canoeist:

To make a common denominator between the fractions, we can multiply the whole equation by s(s-5):
![s(s-5)[\frac{18}{s} + \frac{4}{s-5} = 3] \\ 18(s-5)+4s=3s(s-5) \\ 18s - 90+4s=3 s^{2} -15s](https://tex.z-dn.net/?f=s%28s-5%29%5B%5Cfrac%7B18%7D%7Bs%7D%20%2B%20%5Cfrac%7B4%7D%7Bs-5%7D%20%3D%203%5D%20%5C%5C%2018%28s-5%29%2B4s%3D3s%28s-5%29%20%5C%5C%2018s%20-%2090%2B4s%3D3%20s%5E%7B2%7D%20-15s)
If we rearrange this, we can turn it into a quadratic equation and factor:

Technically, either of these solutions would work when plugged into the original equation, but I would use the second solution because it's a little "neater." We have the speed for the first part of the trip (9 mph); now we just need to subtract 5mph to get the speed for the second part of the trip.

The canoeist's speed on the first part of the trip was 9mph, and their speed on the second part was 4mph.
Answer:
Air travels 6,920 meters in 20 seconds.
Step-by-step explanation:
If in one second air travels 346 meters, and you want to find out how many meters air travels in 20 seconds, then just multiply 346 by 20.