Arithmetic Sequences

What is the sum, $S$, of the finite sequence given by $a_n$?

What is the sum, $S$, of the finite sequence given by $a_n$?

What is the sum, $S$, of the finite sequence given by $a_n$?

What is the sum, $S$, of the finite sequence given by $a_n$?

What is the sum, $S$, of the finite sequence given by $a_n$?

What is the sum, $S$, of the finite sequence given by $a_n$?

What is the sum, $S$, of the finite sequence given by $a_n$?