Tag: maths

Questions Related to maths

The % of total quantity represented by a $60^{circ}$ sector in a pie diagram is 

  1. $6 \displaystyle \frac{1}{4}$ %

  2. $16\, \displaystyle \frac{2}{3}$ %

  3. $11\, \displaystyle \frac{1}{9}$ %

  4. None


Correct Option: B
Explanation:

$\displaystyle \frac{x}{100}\, \times\, 360\, =\, 60^{\circ}$


$x\, =\, 60\, \times\, \displaystyle \frac{100}{360}\, =\, \displaystyle \frac{100}{6}\, =\, 16\, \displaystyle \frac{2}{3}$ %

When the circumference of a circle decreases from $3\, \pi$ to $\pi$ , its area decreases by

  1. $16\, \displaystyle \frac{2}{3}$ %

  2. $66\, \displaystyle \frac{2}{3}$ %

  3. $88\, \displaystyle \frac{8}{9}$ %

  4. $12\, \displaystyle \frac{1}{2}$ %


Correct Option: C
Explanation:

Ratio of circumference = 3 : 1
Ratio of radii = 3 : 1
$\therefore$ ratio of areas $=\, 3^2\, : 1^2\, 9\, :\, 1$
% decrease in area $=\, \displaystyle \frac{8}{9}\, \times\, 100$
$=\, 88\, \displaystyle \frac{8}{9}$ %

Rajan earns $33\frac {1}{3}$ % less than Ram. Then by how much percent is Ram's income above Rajan's?

  1. 40%

  2. 50%

  3. 60%

  4. 70%


Correct Option: B
Explanation:

Given that, Rajan earns $33\dfrac{1}{3}$ percent  less than Ram.


Let, the income of Ram is 100 r.s.


Then the income of Rajan is$=100-33\dfrac{1}{3}=100-\dfrac{100}{3}=\dfrac{200}{3}$


Difference in income is $=100-\dfrac{200}{3}=\dfrac{100}{3}$


Now, required income in percent $=\dfrac{100\times \dfrac{100}{3}}{\dfrac{200}{3}}=50\,$ percent


Hence, this is the answer. 

$\displaystyle 12\frac{1}{2}$% of .......... = 35% of 700

  1. $490$

  2. $500$

  3. $1960$

  4. $1800$


Correct Option: C
Explanation:

Let the blank space be $x$ and we solve the given equality $12\dfrac { 1 }{ 2 }$% of $x=35$% of $700$ as follows:


$\dfrac { 12\dfrac { 1 }{ 2 }  }{ 100 } \times x=\dfrac { 35 }{ 100 } \times 700$

$ \Rightarrow \dfrac { \dfrac { 25 }{ 2 }  }{ 100 } \times x=35\times 7$

$ \Rightarrow \dfrac { 25 }{ 200 } \times x=245$

$ \Rightarrow \dfrac { x }{ 8 } =245$

$ \Rightarrow x=245\times 8$

$ \Rightarrow x=1960$

Hence, $12\dfrac { 1 }{ 2 }$% of $1960=35$% of $700$.

$16$ is what percent of $12$?

  1. $133.33$%

  2. $100$%

  3. $120$%

  4. $150$%


Correct Option: A
Explanation:

$\cfrac{16}{12}=\cfrac{Percent}{100}$

$Percent=\cfrac{16}{12}\times 100$
$\cfrac{400}{3}=133.33$%

If $30\%$ of $140=x\%$ of $840$, then the value of $x$ is _________.

  1. $5$

  2. $15$

  3. $24$

  4. $60$


Correct Option: A
Explanation:

Given that $30\%$ of $140$ $=$ $x\%$ of $840$

Thus $\dfrac {30}{100}\times 140=\dfrac {x}{100}\times 840$
$\Rightarrow 42=8.4x$
$\Rightarrow x=5$

What is $25\%$ of $25\%$?

  1. $6.25$

  2. $0.625$

  3. $0.0625$

  4. $0.00625$


Correct Option: C
Explanation:

We need to find $25\%$ of $25\%$

We know $25\%=\dfrac {25}{100}=0.25$
Thus $25\%$ of $0.25$ is equal to
$=\dfrac {25}{100}\times 0.25$
$=0.0625$
Hence, option C is correct.

If $p$ is $95\%$ of $q$, then what percentage of $p$ is $q$?

  1. 105%

  2. 105.3%

  3. 110%

  4. 115%


Correct Option: B
Explanation:

$p=\cfrac{95q}{100}$

$\therefore \cfrac{q}{p} \times 100 = \cfrac{100}{95} \times 100=105.3\%$

Say True or False.
The measure of an obtuse angle $< 90^o$.

  1. True

  2. False


Correct Option: B
Explanation:

False
The measure of an obtuse angle is greater than $90^o$ but less than $180^o$.

An angle whose measure is the sum of the measures of two right angles is _______.

  1. Acute

  2. Obtuse

  3. Right

  4. Straight


Correct Option: D
Explanation:

Measure of a right angle is $90^ \circ$

Measure of a straight angle is $180^ \circ$
Sum of the measure of two right angles is $(90+90)^ \circ=180^ \circ$
Thus an angle whose measure is the sum of two right angles is $Straight$