The sum of 11 terms of an AP whose middle term s 30 is
(1) 320 (2)330 (3)340 (4)350
n=11 (this is the total no of terms)
(a1 + a11)/2 = 30 (sum of first and eventh term)
which gives a1 + a11 = 60 (first and 11th term)
now sum of AP = n x (a1 + a11) /2
= 11 x 60 /2
= 11 x 30
= 330
Hope this helps. Thumbs up if you comprehendo ! xD