Question

The sum of the first 55 term of an A.P is 3300. Find the 28th term.

Answer 1

Let the first term be a and common difference be d.
Then sum of first 55 terms =$\frac{55}{2}(2a+54d)=55a+1485d=3300$
$\to a+27d=60........\left(i\right)$
28th term = a +(28 - 1) d = a + 27 d.
Hence, from (i), the 28th term is 60.