The $20^{th}$ term of the $A.P.$ $1, 11, 21, \ldots$ is........

Find the $12^{th}$ term and the $24^{th}$ term of the $A.P.$ $9, 13, 17, \ldots$

Which term of the $A.P.$ $112, 107, 102, \ldots$ is its first negative term?

For the $A.P.$ $4, 8, 12, 16, \ldots$,$T_{40} - T_{30} = \ldots$

To clear a debt,Ajaybhai has to pay $Rs. 100$ in the first monthly instalment,$Rs. 150$ in the second monthly instalment,and onwards he has to pay in each monthly instalment $Rs. 50$ more than what was paid in the previous instalment. He has to pay $24$ monthly instalments in all. What amount will he pay in the $24^{th}$ instalment?

The $n^{th}$ term of an $A.P.$ is given by $T_n = 3n - 1$. For this $A.P.$,the common difference $d = \ldots$