Question

in a ap middle term is 25 and it contains 9 termsd what is the sum of all terms of the ap

Answer 1

middle term is 5th term
so a5=a+4d=25

sum=
$\frac{n}{2} \times \frac{2a + (n - 1)d}{1}$
=9/2 * (2a+ 8d)
=9*(a+4d)
=9*25
=225