21.

$\mathrm{ABCD} \mathrm{is} \mathrm{a} \mathrm{rhombus}. \mathrm{If} \angle \mathrm{ACB} = 30°, \mathrm{then} \angle \mathrm{ADB} \mathrm{is}$

• 30⁰

• 120⁰

• 60⁰

• 45⁰

Difference of two natural numbers is always

• an integer

• a natural number

• a whole number

• a positive number

$\mathrm{One} \mathrm{factor} \mathrm{of} 2{\mathrm{x}}^2 - 9\mathrm{x} - 26 \mathrm{is}$

• x + 1

• x + 2

• x + 3

• x + 4

$\mathrm{If} \mathrm{a} : \mathrm{b} = 4 : 5, \mathrm{b} :\hspace{0.17em}\mathrm{c} = 6 : 9, \mathrm{c} : \mathrm{d} = 15 : 19, \mathrm{then} \mathrm{a} : \mathrm{b} : \mathrm{c} : \mathrm{d} \mathrm{is}$

• 8 : 10 : 15 : 19

• 10 : 11 : 15 : 19

• 8 : 9 : 15 : 19

• 19 : 15 : 6 : 8

$\mathrm{HCF} \mathrm{of} \frac{2}{5}, \frac{8}{35}, \frac{4}{15} \mathrm{and} \frac{6}{25} \mathrm{is}$

• $\frac{1}{525}$

• $\frac{2}{525}$

• $\frac{1}{552}$

• $\frac{2}{255}$

$\frac{519 \times 519 - 81 \times 81}{519 \times 519 + 2 \times 519 \times 81 + 81 \times 81} = ?$

• $\frac{73}{200}$

• $\frac{73}{100}$

• $\frac{100}{78}$

• $\frac{200}{73}$

$\mathrm{Faactors} \mathrm{of} \left[1 - \frac{1}{{\left(\mathrm{a} - \mathrm{b}\right)}^{ - 2}}\right] \mathrm{will} \mathrm{be}$

• $\left(1 + \mathrm{a} - \mathrm{b}\right)\left(1 - \mathrm{a} + \mathrm{b}\right)$

• $\left(1 + \mathrm{a} - \mathrm{b}\right)\left(1 + \mathrm{a} + \mathrm{b}\right)$

• $\left(1 +\hspace{0.17em}a - b\right)\left(1 - a - b\right)$

• $\left(1 +\hspace{0.17em}\mathrm{a} +\hspace{0.17em}\mathrm{b}\right)\left(1 + \mathrm{a} +\hspace{0.17em}\mathrm{b}\right)$

HCF of two numbers is 9 and their LCM is 270. If the sum of the numbers is 99, their difference is equal to

• 18

• 15

• 12

• 9

Mode of the given data 25, 23, 22, 21, 24, 23, 25, 23, 22, 21, 23, 24, 23, 22, 23 is

• 23

• 22

• 21

• 24

$$\begin{gathered} \mathrm{If} \mathrm{the} \mathrm{perimeter} \mathrm{of} \mathrm{right} \mathrm{angled} \mathrm{isosceles} \mathrm{triangle} \mathrm{is} (4\sqrt{2} + 4) \mathrm{cm}, \\ \mathrm{then} \mathrm{the} \mathrm{length} \mathrm{of} \mathrm{the} \mathrm{hypotenuse} \mathrm{is} \end{gathered}$$

• 4cm

• 6cm

• 8cm

• 10cm