Question

math answers the following this take time but it worth it points also 2x​

Answer 1

Solution XVII:-

$\sf{Let \: cost \: of \: notebook \: is \: Rs. \: x}$

$\sf{And, cost \: of \: pen \: be \: Rs. y}$

$\sf{It \: is \: given \: that:-}$

• $\sf{Cost \: of \: notebook = 2× Cost \: of \: Pen.}$

$\sf{\therefore \: x = 2y}$

$\implies\sf{x-2y = 0}$

So, x-2y=0 is the linear equation in two variables.

Solution XVIII:-

$\sf{\underline{\red{Given:-}}}$

• $\sf{Radius\: of\: sphere = 7cm.}$

$\sf{\underline{\red{To\: Find:-}}}$

• $\sf{Curved\: Surface\: Area\: Of\: Sphere.}$

$\sf{\underline{\red{Formula\: Used:-}}}$

• $\sf{ CSA\: of\: sphere = 2\pi {r}^{2} }$

$\implies\sf{2 \times \frac{22}{7} \times {(7)}^{2} }$

$\implies\sf{2 \times \frac{22}{\cancel{7}}\times \cancel{7} \times 7}$

$\implies\sf{2 \times 22 \times 7}$

$\implies\sf{44 \times 7}$

$\implies\sf\green{308cm^2}$

Solution XIX:-

$\sf\purple{Mode = 13}$

$\sf{Because \: it \: has \: more \: frequency.}$

Solution XX:-

5 are added to each observation of data.

Hence, Each value will be increased by 5. And, middle value will also increase by 5.

Hence, Difference in median = 5.

Solution XXI:-

$\sf{\underline{\red{Given:-}}}$

$\sf{P(E) = 0.37.}$

$\sf{Probability\: = 1-0.37}$

$\sf{Probability\: = \fbox\green{0.63}}$

Solution XXII:-

$\red\dashrightarrow\sf\bold{ \frac{1}{ \sqrt{7} - \sqrt{4}} }$

$\red\dashrightarrow\sf\bold{ \frac{1}{ \sqrt{7} - \sqrt{4} } \times \frac{ \sqrt{7} + \sqrt{4} }{ \sqrt{7} + \sqrt{4} } }$

$\red\dashrightarrow\sf\bold{ \frac{ \sqrt{7} + \sqrt{4} }{7 - 4}}$

$\red\dashrightarrow\sf\bold{ \frac{ \sqrt{7} + \sqrt{4} }{3} }$