Question

find the value of the middle most term of the ap -15,-11.......53

Answer 1

-15,-11.....53
d = -11-(-15) = -11+15 = 4    d=4
L/aⁿ = a+(n-1)d
53= -15 + (n-1)4
53+15 = 4n-4
68+4 = 4n
72/4 = n
18 = n
we have to find the value of the middle term. so n/2 = 18/2 = 9th term will be the middle term
9th term = a+(9-1)d = -15+ (8)4 = -15+32 = 17
So, the answer is 17.

hope it helps.. :)