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…

The sum of the first 16 terms of an AP whose first term and third term are 5 and 15 respectively is

The common difference of an A.P., the sum of whose n terms is S<sub>n</sub>, is

If in an A.P., S<sub>n</sub> = n<sup>2</sup>p and S<sub>m</sub> = m<sup>2</…

In an AP, S<sub>p</sub> = q, S<sub>q</sub> = p and S denotes the sum of first r terms. Then, S&l…

If the first term of an A.P. is a and nth term is b, then its common difference is

In an A.P., if d = -4, n = 7, a<sub>n</sub> = 4, then a is

The common difference of the A.P. $$\frac{1}{{2b}},$$ $$\frac{{1 - 6b}}{{2b}},$$  $$\frac{{1 - 12b}}{{2b}},$$ &…