Given:
The first two terms in an arithmetic progression are -2 and 5.
The last term in the progression is the only number in the progression that is greater than 200.
To find:
The sum of all the terms in the progression.
Solution:
We have,
First term : 
Common difference : 


nth term of an A.P. is

where, a is first term and d is common difference.

According to the equation,
.



Divide both sides by 7.

Add 1 on both sides.

So, least possible integer value is 30. It means, A.P. has 30 term.
Sum of n terms of an A.P. is
![S_n=\dfrac{n}{2}[2a+(n-1)d]](https://tex.z-dn.net/?f=S_n%3D%5Cdfrac%7Bn%7D%7B2%7D%5B2a%2B%28n-1%29d%5D)
Substituting n=30, a=-2 and d=7, we get
![S_{30}=\dfrac{30}{2}[2(-2)+(30-1)7]](https://tex.z-dn.net/?f=S_%7B30%7D%3D%5Cdfrac%7B30%7D%7B2%7D%5B2%28-2%29%2B%2830-1%297%5D)
![S_{30}=15[-4+(29)7]](https://tex.z-dn.net/?f=S_%7B30%7D%3D15%5B-4%2B%2829%297%5D)
![S_{30}=15[-4+203]](https://tex.z-dn.net/?f=S_%7B30%7D%3D15%5B-4%2B203%5D)


Therefore, the sum of all the terms in the progression is 2985.
The decimal for 77/200 is 0.385
Step-by-step explanation:
All has been answered... send me any questions at comments
Answer:
If you want a simple average, you can add all the speeds you see and divide them by the number of how many they are.
So firstly you have to calculate the speed of the first point, which is:
20 miles/0.5 hour
That means: 40 miles/hour
That would be your first "speed"
Then you calculate all of them :speed1+speed2+speed3 = something.
As an example: 20miles/hr + 40miles/hr+0miles/hr = 60miles/hr
Then, you divide it by how many "speeds" they are: 60miles/hr divided by 3 if I continue my previous example.
It is my first answer, and I hope I could help you a bit!
Sorry for the awkward English, as it is not my mother tongue.
Step-by-step explanation: