Question

The value of $\sqrt{20}\times \sqrt{5}$ is,

(a) 10

(b)$3\sqrt{5}$

(c)$5\sqrt{5}$

(d)$3\sqrt{3}$

Answer 1

$\sqrt{20}\times \sqrt{5}$=
$\sqrt{5}\times 2\times \sqrt{5}$=
${\sqrt{5}}^2\times 2$=
$5\times 2$=
$10$

Hence, the correct answer is option (a)