The sum of an Arithmetic Series is given as:

where,
d = Common Difference = Difference of any two consecutive terms.
So,
d = 8
a1 = First term = 1
Using the values, we get:

The above equation gives the formula for n terms of an Arithmetic Series.
So, option A is the correct answer
Well im not sure about that but I think the answer is 42.5
I hope it helps you get it right
Hello There!
Simply do this:
2/7 / 2 = 1/7
Your answer is 1/7
Hope This Helps You!
Good Luck :)
- Hannah ❤