The sides of a triangle are distinct positive integers in an arithmetic progression. If the smallest side is $10$, the number of such triangles is
Maximum value of sum of arithmetic progression $50, 48, 46, 44 ........$ is :-
If the sum of the first $n$ terms of a series be $5{n^2} + 2n$, then its second term is
A series whose $n^{th}$ term is $\left( {\frac{n}{x}} \right) + y,$ the sum of $r$ terms will be
The sum of $n$ arithmetic means between $a$ and $b$, is