200 views

0 votes

A series $\text{S1}$ of five positive integers is such that the third term is half the first term and the fifth term is $20$ more than the first term. In series $\text{S2}$, the $n$th term defined as the difference between the $(n+1)$ term and the $n^{\text{th}}$ term of series $\text{S1}$, is an arithmetic progression with a common difference of $30$.

What is the average value of the terms of series $\text{S1}$?

- $60$
- $70$
- $80$
- Average is not an integer