Find the sum of all the 11 terms of an AP whose middle most term is 30.


No of terms = 11 as it is even


Middle term will be i.e. 6th term


Let the first term be a and common difference be d of an AP


As


an = a + (n - 1)d


a6 = a + (6 - 1)d


30 = a + 5d [ eqn 1]


Now as we know,





[ using eqn 1]




29
1