I have this question and I don't understand what it's asking for. It says evaluate, is it asking for the missing term or what?

Question

The sequence 21, 23, 25, 27, 29, ..., 41 has 11 terms. Evaluate the related series.

* 320
* 341
* 300
* 166

Very confused, any insight on how to solve this would be helpful :)

Answer 1

In simple terms, for a sequence you would list the terms,
in a series you would add the terms

so you want
21+23+25+ ... + 41

this is an arithmetic series with
a = 21, d=2 and n = 11

the sum of those terms
using sum = n/2(first term + last term)
= 11/2(21+41)
= 341

Answer 2

The way the question is phrased suggests that not all of it has actually been posted. "Evaluate the related series" doesn't mean anything on its own - at least, not to me. Has your teacher defined a "related series" to be the sum of the individual elements of that series? This is one of those questions where its easy enough to guess what's required - which is what has been written above - but this seems not actually to have been ASKED for!