If the sum of the $10$ terms of an $A.P.$ is $4$ times the sum of its $5$ terms,then the ratio of the first term to the common difference is:

$A$ man saves $200$ in each of the first three months of his service. In each of the subsequent months, his saving increases by $40$ compared to the saving of the immediately previous month. His total saving from the start of service will be $11040$ after ............ months.

If the roots of the equation $x^3 - 12x^2 + 39x - 28 = 0$ are in an arithmetic progression,what is the common difference?

If the $p^{th}$ term of an arithmetic progression is $q$ and the $q^{th}$ term is $p$,then its $n^{th}$ term is:

Find the mean of the first $n$ terms of the $A$.$P$. $a, (a + d), (a + 2d), \dots$

In an arithmetic progression,if $S_{40} = 1030$ and $S_{12} = 57$,then $S_{30} - S_{10}$ is equal to: