Question

Choose the correct answer in each of the following questions:

The common difference of the AP $\frac{1}{3},\frac{1-3b}{3},\frac{1-6b}{3},...$ is [CBSE 2013]

(a) $\frac{1}{3}$ (b) $\frac{-1}{3}$ (c) b (d) −b

Answer 1

The given AP is $\frac{1}{3},\frac{1-3b}{3},\frac{1-6b}{3},...$ .

∴ Common difference, d = $\frac{1-3b}{3}-\frac{1}{3}=\frac{1-3b-1}{3}=\frac{-3b}{3}=-b$

Hence, the correct answer is option D.