Tag: maths

Questions Related to maths

A dealer pays following VAT @ of 14% on 20th April Rs. 2500, 20th May Rs. 1200. Find his sales for March and April.

  1. $16428.55$

  2. $26428.55$

  3. $36428.55$

  4. $46428.55$


Correct Option: B
Explanation:

Sales for April:
Total VAT = VAT% of sales
$2500=\cfrac{14}{100}\times sales$
Sales of April $= Rs. 17857.14$
Sales for May:
Total VAT = VAT% of sales
$1200=\cfrac{14}{100}\times sales$
Sales of April $= Rs. 8571.42$
Total sales for March and April $= 17857.14 + 8571.41 = Rs. 26428.55$

Shri. Batliwala sold shares of Rs $30350$ and purchased shares of Rs $69650$ in a day. He paid $0.1\%$ brokerage on both sale and purchase of shares. $18\%$ GST was charged on the brokerage. Find his total expenditure on brokerage and tax.

  1. $120$

  2. $118$

  3. $139.5$

  4. $105$


Correct Option: B
Explanation:
Value of shares sold = $30350$
Brokerage =$0.1%$
$\therefore$ brokerage  value =$\cfrac{0.1}{100}\times30350$
= $303.5/10$=$30.35$
Value of shares purchased =$69650$
Brokerage =$0.1%$
$ \text {brokerage value} =\cfrac{0.1}{100}\times69650$
=$696.5/10$
=$69.65$
$\therefore$ total  brokerage  value =$(30.35+69.65)$
=$Rs 100$
$G. S. T$= $18%$ of brokerage  value 
$\therefore$ amount of gst = $\cfrac{18}{100}\times100$
=$18$
$\therefore$  total amount of brokerage +gst =$100$+$18$
=$118$.

The range of values of $\lambda$ for which the circles $ { x }^{ 2 }+{ y }^{ 2 }=4$ and ${ x }^{ 2 }+{ y }^{ 2 }-2\lambda y+5=0$ have two common tangents only is-

  1. $\lambda \epsilon \left( -\sqrt { 5 } ,\sqrt { 5 } \right) $

  2. $\lambda <-\sqrt { 5 } or\quad \lambda >\sqrt { 5 }$

  3. $-\sqrt { 5 } <\lambda <1$

  4. none of these


Correct Option: A

The range of values of x for which the circles ${ x }^{ 2 }+{ y }^{ 2 }=4$ and$ { x }^{ 2 }+{ y }^{ 2 }+2xy+5=0\quad$ have two on tangents only is= 

  1. $\left( -\sqrt { 5 } ,\sqrt { 5 } \right)$

  2. $\lambda <=\sqrt { 5 } or\quad \lambda >\sqrt { 5 }$

  3. $-\sqrt { 5 } <\lambda <1$

  4. none of these


Correct Option: A

Intercept of a tangent between two parallel tangents to a circle subtends a right angle at the centre.

  1. True

  2. False


Correct Option: A

In the given figure, $AD\ and AE$ are the tangents to a circle with centre $O\ and BC$ touches the circle at $F$. If $AE=5\ cm$ then perimeter of $\triangle ABC$ is 

  1. $15\ cm$

  2. $10\ cm$

  3. $22.5\ cm$

  4. $20\ cm$


Correct Option: A

$\overline { M N }$ and $\overline { M Q }$ are two tangents from a point $M$ to a circle with centre $0$ If $m \angle N O Q = 120 ^ { \circ } ,$ then ?

  1. $N Q = M N = M Q$

  2. $N Q = O M$

  3. $O Q = O M$

  4. $O N = M N$


Correct Option: A

If $\triangle ABC$ is isoscles with $AB=AC$ and $C(O,r)$ is the incircle of the of the $\triangle BAC=30^{o}$. The tangent at $C$ intersects $AB$ at a point $D$, then $L$ trisects $BC$.

  1. True

  2. False


Correct Option: B

The chord of contact of the pair of tangents to the circle $x^2+y^2=1$ drawn from any point on the line $2x+y=4$ passes through a fixed point. 

  1. True

  2. False


Correct Option: A
Explanation:

If chords are drawn to the circle from a fixed point $(x _1,y _1)$ and then tangents are drawn at point of contact, the point of intersection of all tangents lie on a fixed point.


The fixed point is called pole and fixed line is called polar.


Equation of polar is $T=0$.

$C:x^2+y^2-1=0$

Equation of polar is $T=0$.

$xx _1+yy _1-1=0$

The line is identical to given line $2x+y-4=0$.

By comparing coefficients, we get,
$\dfrac{x _1}{2}=\dfrac{y _1}{1}=\dfrac{-1}{-4}$

$x _1=\dfrac{1}{2},y _1=\dfrac{1}{4}$

Hence, the fixed point is $(\dfrac{1}{2}, \dfrac{1}{4})$.

From a point $P$ which is at a distance of $13$ cm from the centre $O$ of a circle of radius $5$ cm, the pair of tangents $PQ$ and $PR$ to the circle are drawn. Then the area of the quadrilateral $PQOR$ is:

  1. $60$ cm$^{2}$

  2. $65$ cm$^{2}$

  3. $30$ cm$^{2}$

  4. $32.5$ cm$^{2}$


Correct Option: A
Explanation:

The radius perpendicular tangent at the pt. of contact, therefore, $OQ\perp PQ$ and $OR\perp PR$
In rt. $\triangle OPQ$, we have
$PQ=\sqrt{OP^{2}-OQ^{2}}$
   $=\sqrt{169-25}=\sqrt{144}=12$ cm
$\Rightarrow $ $PR=12$ cm (Two tangents from the same external pt. to a circle are equal)
Now area of quad. $PQOR=2\times $Area of $\triangle POQ$
   $\displaystyle =\left ( 2\times \frac{1}{2}\times 12\times 5 \right )$ cm$^{2}=60$ cm$^{2}$