So, from the first term, to the fifteen term, there are 14 terms to go through.
that means, if say the common difference is say "d", we have to add "d" 14 times, to get to the 15th term, lemme make a quick table,
and surely you know how much that is.
that means, if say the common difference is say "d", we have to add "d" 14 times, to get to the 15th term, lemme make a quick table,
and surely you know how much that is.