Tag: business mathematics and statistics

Questions Related to business mathematics and statistics

Given the marginal cost function $\dfrac{2x}{3}+3-\dfrac{16}{x^2}$, find  average cost function.

  1. $\dfrac{1}{3}x^2+3x-7+\dfrac{16}{x}$

  2. $\dfrac{1}{2}x^2+3x-7+\dfrac{16}{x}$

  3. $\dfrac{1}{4}x^2+3x-7+\dfrac{16}{x}$

  4. None of these


Correct Option: A
Explanation:

$\Rightarrow$  We have $MC=\dfrac{2x}{3}+3-\dfrac{16}{x^2}$


$\Rightarrow$  $Average\,\,cost=\int (MC)dx$ 


$\Rightarrow$   $Average\,\,cost=\int (\dfrac{2x}{3}+3-\dfrac{16}{x^2})dx$


$\therefore$   $Average\,\,cost=\dfrac{2x^2}{2\times 3}+3x-7+\dfrac{16}{x}$

$\Rightarrow$   $Average\,\,cost=\dfrac{1}{3}x^2+3x-7+\dfrac{16}{x}$

The cost function of a firm $C(x)=3x^2-2x+3$. Find the average cost when $x=3$.

  1. 8

  2. 9

  3. 10

  4. 12


Correct Option: A
Explanation:

$\Rightarrow$  We have, $C(x)=3x^2-2x+3$

$\Rightarrow$  Average cost = $\dfrac{C(x)}{x}$

$\Rightarrow$  Average cost = $\dfrac{3x^2-2x+3}{x}$

$\Rightarrow$  Average cost = $3x-2+\dfrac{3}{x}$.

$\Rightarrow$  Substitute value of $x=3$,
$\Rightarrow$  Average cost = $3\times 3-2+\dfrac{3}{3}=9-2+1=8$
$\therefore$    $Average\, cost\,=8$. 

If the demanding Law is given by $q = \dfrac{20}{p+1}$, find the elasticity of demand with respect to price at the point when $p = 3.$

  1. $\dfrac43$

  2. $-\dfrac34$

  3. $\dfrac23$

  4. $-\dfrac32$


Correct Option: B
Explanation:
Elasticity of demand $=\cfrac{\cfrac{dq}{q}}{\cfrac{dp}{p}}=-\cfrac{p}{(p+1)}$
When $p=3$
Elasticity of demand $=-\cfrac{3}{4}$

If the total cost function for a manufacturer is given by $C =\dfrac{5x^2}{\sqrt(x^2+3)}+5000$, find marginal cost function.

  1. $\dfrac{3x(x^2+6)}{(x^2+3)^{(3/2)}}$

  2. $\dfrac{4x(x^2+6)}{(x^2+3)^{(3/2)}}$

  3. $\dfrac{5x(x^2+6)}{(x^2+3)^{(3/2)}}$

  4. None of these


Correct Option: C
Explanation:

Given cost function $C\left(x\right)=\dfrac{5x^2}{\sqrt{\left(x^2+3\right)}}+5000$


Marginal cost function is given by $C'\left(x\right)$

$C'\left(x\right)=\dfrac{\left(\sqrt{x^2+3}\right)\left(10x\right)-\dfrac{5x^2}{2\sqrt{x^2+3}}\times\left({2x+10}\right)}{\left(\sqrt{x^2+3}\right)^2}$

$\dfrac{d}{dx}\left(\dfrac{u}{v}\right)=\dfrac{v\dfrac{du}{dx}-u\dfrac{dv}{dx}}{v^2}$

$C'\left(x\right)=\dfrac{2\left(x^2+3\right)\left(10x\right)-5x^2\left(2x\right)}{2\left(\sqrt{x^2+3}\right)^3}=\dfrac{5x\left(x^2+6\right)}{\left(x^2+3\right)^\tfrac{3}{2}}$

State, which of the following variables are continuous and which are discrete :


Sizes of shoes is discrete
If true then enter $1$ and if false then enter $0$

  1. $1$

  2. $0$

  3. Can't determine

  4. None of these


Correct Option: A
Explanation:

Size of a shoe can have integer values only. Hence, it is a discrete variable.

Say true or false:
Daily temperature is discrete variable.

  1. True

  2. False


Correct Option: B
Explanation:

Daily temperature can have any integer as well as rational values. Hence, it is a continuous variable.

Say true or false:

Sizes of the shoe are discrete variables.

  1. True

  2. False


Correct Option: A
Explanation:

Size of shoe can have have only integer value. Hence, it is a discrete variable.

Are you a girl or boy is an example of ______ variable.

  1. continuous

  2. dependent

  3. discrete

  4. nominal


Correct Option: C
Explanation:

A discrete variable is a variable whose value is obtained by counting.
So, are you a girl or boy is an example of discrete variable.
Since it is answerable.

Which one of the statement is discrete variable?

  1. weight of animals in zoo

  2. distance travelled between colleges

  3. number of heads by flipping a coins

  4. height of animals in park


Correct Option: C
Explanation:

Discrete variables are countable in a finite amount of time.
So, number of heads when flipping a coin is a discrete variable statement because once the coin is flipped, we will get head or tail result.

The statement "number of heads when flipping a coin" is an example of ______ variable.

  1. continuous

  2. dependent

  3. discrete

  4. nominal


Correct Option: C
Explanation:

Discrete variables are countable in a finite amount of time.
So, number of heads when flipping a coin is a discrete variable statement because once the coin is flipped, we will get head or tail result.