If $k, (2k-1)$ and $(2k+1)$ are the three successive terms of an $AP$, find the value of $k$.

If $18, a, (b-3)$are in $AP$, then find the value of $(2a-b)$

If the numbers $a, 9, b, 25$ from an $AP$, find $a$ and $b$.

If the numbers $(2n–1), (3n+2)$ and $(6n-1)$are in $AP$, find the value of $n$ and the numbers

How many three-digit natural numbers are divisible by $7$?

How many three-digit natural numbers are divisible by $9$?

If the sum of first $m$terms of an $AP$ is $(2m^2+3m)$ then what is its second term?

What is the sum of first $n$ terms of the $AP a, 3a, 5a, \dots ..$

What is the $5^{th}$ term from the end of the $AP 2, 7, 12, \dots ., 47?$