Find the n<sup>th</sup> term of the following sequence :</br> 5 + 55 + 555 + . . . . T<sub>n<…

The first and last term of an A.P. are a and l respectively. If S is the sum of all the terms of the A.P. and the common…

If S<sub>n</sub> denotes the sum of the first r terms of an A.P. Then, S<sub>3n</sub> : (S<su…

If 18<sup>th</sup> and 11<sup>th</sup> term of an A.P. are in the ratio 3 : 2, then its 21<su…

The sum of n terms of two A.P.’s are in the ratio 5n + 4 : 9n + 6. Then, the ratio of their 18<sup>th</su…

What is the sum of the first 9 terms of an arithmetic progression if the first term is 7 and last term is 55?

If the sum of it terms of an A.P. is 2n<sup>2</sup> + 5n, then its nth term is

A boy agrees to work at the rate of one rupee on the first day, two rupees on the second day, and four rupees on third d…