Arithmetic Sequence Question

[Andrew Sameh]

I haven't been able to solve this question correctly
Anyone could help with this?
The question is:
The 9th term of an arithmetic series is 2.5
The sum of the 2nd term and the 5th term of this series is 27
Find the sum of the first 100terms of the series

 

[Deleted member 4993]

I haven't been able to solve this question correctly
Anyone could help with this?
The question is:
The 9th term of an arithmetic series is 2.5
The sum of the 2nd term and the 5th term of this series is 27
Find the sum of the first 100terms of the series

if the first term of the sequence is 'a ' and the common difference is ' d ', then

What is the expression for the 9th term?

 

[Steven G]

1st term is a
2nd term is a + 1d
3rd term is a + 2d
4th term is a + 3d
5th term is a + 4d
...
9th term is ???? = 2.5
....
100th term is ?????

Get two equations involving a and d, solve for a and d and then calculate the 100th term