Question:
Choose the correct answer in each of the following questions:
The common difference of the AP $\frac{1}{p}, \frac{1-p}{p}, \frac{1-2 p}{p}, \ldots$ is
(a) $p$
(b) $-p$
(c) $-1$
(d) 1
Solution:
The given $\mathrm{AP}$ is $\frac{1}{p}, \frac{1-p}{p}, \frac{1-2 p}{p}, \ldots$
$\therefore$ Common difference, $d=\frac{1-p}{p}-\frac{1}{p}=\frac{1-p-1}{p}=\frac{-p}{p}=-1$
Hence, the correct answer is option C.