$\sqrt{10}\times \sqrt{15}=?$
(a) $\sqrt{25}$
(b) $5\sqrt{6}$
(c) $6\sqrt{5}$
(d) none of these

Q. Mark (✓) against the correct answer

${\left\{6^{-1}+{\left(\frac{3}{2}\right)}^{-1}\right\}}^{-1}=?$

(a) $\frac{2}{3}$
(b) $\frac{5}{6}$
(c) $\frac{6}{5}$
(d) none of these

Q. 54 ÷ 3 of 6 + 9 = ?
(a) 117
(b) 12
(c) $\frac{6}{5}$
(d) none of these

Q.

If $(-7-24i{)}^{1/2}$=x-iy, then $x^2$+$y^2$=

Q. Mark the correct alternative in each of the following:

$\left(-2\right)÷\left(-\frac{5}{3}\right)=$

(a) $\frac{5}{6}$ (b) $-\frac{5}{6}$ (c) $\frac{6}{5}$ (d) $\frac{-6}{5}$