Question

If $3\sqrt{5}+\sqrt{125}=17.88$, then what will be the value of $\sqrt{80}+6\sqrt{5}$ ?

• A. 13.41
• B. 20.46
• C. 21.66
• D. 22.35

Answer 1

The correct option is D 22.35

$3\sqrt{5}+\sqrt{125}=17.88$
$\Rightarrow 3\sqrt{5}+\sqrt{25\times 5}=17.88$
$3\sqrt{5}+5\sqrt{5}=17.88$
$\Rightarrow 8\sqrt{5}=17.88$$\sqrt{5}=2.235$
$\therefore \sqrt{80}+6\sqrt{5}=\sqrt{16\times 5}+6\sqrt{5}$
$4\sqrt{5}+6\sqrt{5}$
$10\sqrt{5}=(10\times 2.235)=22.35$