Mathematics : Sequences and Series

Let S_n denotes the sum of first n terms of an AP.If S₄ = - 34, S₅ = - 60 and S₆ = - 93, then the common difference and the first term of the AP are respectively

• - 7, 2

• 7, - 4

• 7, - 2

• - 7, - 2

An AP has the property that the sum of first ten terms is half the sum of next ten terms. If the second term is 13, then the common difference is

• 3

• 2

• 5

• 4

If a, b, c are in AP, b - a, c - b and a are in GP, then a: b : c is

• 1 : 2 : 3

• 1 : 3 : 5

• 2 : 3 : 4

• 1 : 2 : 4