Sequence and Series - Arithmetic Progression

The \(n^{th}\) term of an arithmetic sequence is given by \(u_n = 5 + 2n\).

1. Write down the common difference.
2. 1. Given that the \(n^{th}\) term of this sequence is \(115\), find the value of \(n\).
   2. For this value of \(n\), find the sum of the sequence.