How many terms are there in 20, 25, 30 . . . . . . 140?

How many terms are there in the GP 5, 20, 80, 320........... 20480?

The n<sup>th</sup> term of an A.P., the sum of whose n terms is S<sub>n</sub>, 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…

If $$\frac{1}{{x + 2}},$$  $$\frac{1}{{x + 3}},$$  $$\frac{1}{{x + 5}}$$   are in A.P. then x…

The sum of the three numbers in A.P is 21 and the product of the first and third number of the sequence is 45. What are …

If S<sub>n</sub> denote the sum of n terms of an A.P. with first term a and common difference d such that $$…

Given A = 2<sup>65</sup> and B = (2<sup>64</sup> + 2<sup>63</sup> + 2<sup>62&l…