If k, 2k – 1 and 2k + 1 are three consecutive terms of an AP, the value of k is

If $$\frac{{5 + 9 + 13 + ...\,{\text{to}}\,n\,{\text{terms}}}}{{7 + 9 + 11 + ...\,{\text{to}}\,\left( {n + 1} \right)\,{…

If the first, second and last term of an A.P. are a, b and 2a respectively, its sum is

The first three terms of an A.P. respectively are 3y – 1, 3y + 5 and 5y + 1. Then, y equals

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…

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

The number of terms of the A.P. 3, 7, 11, 15, ....... to be taken so that the sum is 406 is

If S<sub>1</sub> is the sum of an arithmetic progression of ‘n’ odd number of terms and S<sub…