If 18, a, b - 3 are in A.P. then a + b =

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

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

How many 2-digit positive integers are divisible by 4 or 9?

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 3<sup>rd</sup> and 6<sup>th</sup> term of an arithmetic progression are 13 and -5 respective…

Which term of the A.P. 24, 21, 18, ............ is the first negative term?

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