ANSWER:
STEP BY STEP EXPLANATION:
<h3>
Answer: B) 30</h3>
Any amount of rotation will not change the angle between the two spokes. This is because each piece of the wheel moves in unison as the rotation is applied. Nothing changes about the wheel. Imagine instead of rotating the wheel, we instead rotated the camera that is capturing the wheel (or the person looking at the wheel rotates their head). This is a good way to see how the wheel itself isn't changing at all, but instead rather just the look of it is changing.
Answer:
The difference between the temperatures in the two countries is 38.3°C.
Step-by-step explanation:
Given:
Temperature in Greenland = - 8.3°C
Temperature in Jamaica = 30°C
To find :
The difference between the temperature in the two countries = ?

Therefore,the difference between the temperatures in the two countries is 38.3°C
Let's begin ! ^_^
You have got informations in your problem that you just have to translate in a "mathematic language".
Company A :
"$40 membership fee and $2 per video stream."
Thanks to that, you can guess :
c = 40 + 2s
Now let's do the same thing to the company B.
Company B :
"charges a one-time $20 membership fee and $4 per video stream."
Therefore, c = 20 + 4s.
I think you have guessed !! =D And yes the system of equation that you have to solve and you're looking for is :
{c=40+2s ( Option B)
c=20+4s.
Second step : For how many video streams will the cost be the same for both companies?
We just have to solve the system :) And there is only one variable, the letter "s".
We know that we have to find equal costs as it is said in the question " the cost be the same for both companies", so :
=> 40 + 2s = 20 +4s
=> 4s - 2s = 40 - 20
=> 2s = 20
=> s = 20/2
=> s = 10
Verification :
Company A :
=> 40 + 2s = 40 + 2*10 = 40 + 20 =60.
Company B :
=> 20 + 4s = 20 + 4*10 = 20 + 40 = 60
As you have seen, the costs are the same for both companies.
We can say that as a conclusion for 10 video streams, the cost will be the same for both companies.
In short, the answer would be : 10.
Let me give you an advice : Usually the word "per" means a multiplication is the mathematic language.
Hope this helps !
Photon
1. v=d/t=7.5/1.5=5 km/h
2. v=d/t=(v1*t1+v2*t2+v3*t3)/(v1+v2+v3)=(15*10+20*10+25*5)/(10+10+5)=
=(150+200+125)/25=475/25=19 m/s