Question

If the middle term of an AP IS 18 then sum of its 11 terms is

Answer 1

Given middle term or the sixth term is 30

Then, a+5d=18m

$sum = \frac{n}{2} (2a + (n - 1)d)$

$= \frac{11}{2}(2a + 10d)$

$= \frac{11}{2} (2 \times 18)$

$= 11 \times 18$

$= 198$