Question:
Choose the correct answer in each of the following questions:
The next term of the AP $\sqrt{7}, \sqrt{28}, \sqrt{63}, \ldots$ is
(a) $\sqrt{70}$
(a) $\sqrt{84}$
(a) $\sqrt{98}$
(d) $\sqrt{112}$
Solution:
The given terms of the AP can be written as $\sqrt{7}, \sqrt{4 \times 7}, \sqrt{9 \times 7}, \ldots$ i.e. $\sqrt{7}, 2 \sqrt{7}, 3 \sqrt{7}, \ldots$
$\therefore$ Next term $=4 \sqrt{7}=\sqrt{16 \times 7}=\sqrt{112}$
Hence, the correct answer is option $D$.