Tag: dividing fractions

Questions Related to dividing fractions

Simplify the following:
$\dfrac {3}{8} \div \dfrac {24}{48} =\dfrac{3}{4}$

  1. True

  2. False


Correct Option: A
Explanation:
$\dfrac{3}{8} \div \dfrac{{24}}{{48}} = \dfrac{3}{8} \times \dfrac{{48}}{{24}} = \dfrac{3}{4}$
Hence, the simplification is true.

Divide the sum of $\displaystyle\frac{65}{12}$ and $\displaystyle\frac{12}{7}$ by their difference.

  1. $\displaystyle\frac{599}{311}$

  2. $\displaystyle\frac{680}{216}$

  3. $\displaystyle\frac{642}{133}$

  4. $\displaystyle\frac{501}{301}$


Correct Option: A
Explanation:

sum of $\dfrac{65}{12}$  and $\dfrac{12}{7} $


$ \dfrac{65}{12} +\dfrac {12}{7}= \dfrac{65\times 7 +12\times 12}{12\times 7} $

                  $=\dfrac{599}{84}$ ......................(1)

difference of  $\dfrac{65}{12}$  and $\dfrac{12}{7} $

$\dfrac{65}{12}-\dfrac{12}{7} = \dfrac{65\times 7 - 12\times 12}{84}= \dfrac{311}{84} $

                  $ =\dfrac{311}{84} $.........................(2)

divide the sum with difference i.e.

dividing equation (1) with equation (2)

$=\dfrac{\dfrac{599}{84}}{\dfrac{311}{84}}$

$=\dfrac{599}{311}$

Divide $\dfrac{15}{38}$ by $\dfrac{-3}{19}$

  1. $\dfrac{-2}{5}$

  2. $\dfrac{-5}{2}$

  3. $\dfrac{2}{5}$

  4. $\dfrac{5}{2}$


Correct Option: B
Explanation:
$\dfrac{15}{38} \div \dfrac{-3}{19}$

$=\dfrac{15\times19}{38 \times -3}$

$=\dfrac{-5}{2}$

$\left(\large{\frac{-5}{3}}\right)^5$ $\div$ $\left(\large{\frac{-5}{3}}\right)^{7}$

  1. $\large{\frac{25}{9}}$

  2. $\large{\frac{9}{25}}$

  3. $\large{\frac{16}{25}}$

  4. $\large{\frac{25}{16}}$


Correct Option: B
Explanation:

$\left(\large{\frac{-5}{3}}\right)^5$ $\div$ $\left(\large{\frac{-5}{3}}\right)^{7}$


$=-\left(\large{\frac{5}{3}}\right)^5$ $\times$ $-\left(\large{\frac{3}{5}}\right)^{7}$


$=\left(\dfrac{3}{5}\right)^2$

$=\dfrac{9}{25}$.

Evaluate: $\dfrac {\left(\dfrac {-3}{5}\right)^{3} \times \left(\dfrac {9}{25}\right)^{2} \times \left(\dfrac {-18}{125}\right)^{o}}{\left(\dfrac {-27}{125}\right) \times \left(\dfrac {-3}{5}\right)}$

  1. $\dfrac{27}{125}$

  2. $-\dfrac{27}{125}$

  3. $\dfrac{64}{125}$

  4. $-\dfrac{64}{125}$


Correct Option: B
Explanation:

$\dfrac {\left(\dfrac {-3}{5}\right)^{3} \times \left(\dfrac {9}{25}\right)^{2} \times \left(\dfrac {-18}{125}\right)^{0}}{\left(\dfrac {-27}{125}\right) \times \left(\dfrac {-3}{5}\right)}=\dfrac{\dfrac{-3^3\times 3^4\times 1}{5^3\times 5^4\times 1}}{\dfrac{3^3\times 3}{5^3\times 5}}=-\dfrac{3^{7-4}}{5^{7-4}}=-\dfrac{27}{125}$

Convert the following into fraction.
$22.5\%$

    • $\dfrac{9}{40}$
  1. $\dfrac{225}{100}$

  2. $\dfrac{22}{100}$

  3. $\dfrac{5}{100}$


Correct Option: A
Explanation:
     $22.5$%
$=\dfrac{22.5}{100}$
$=\dfrac{48}{2}\times \dfrac{1}{100}$
$=\dfrac{9}{40}$

Evaluate the following :

$\displaystyle  8 \times \dfrac {\dfrac{5}{24}}{\dfrac {7}{12}} $.

  1. $\displaystyle \frac {5 }{24}$

  2. $\displaystyle \frac {20}{7}$

  3. $\displaystyle \frac {2}{7}$

  4. $\displaystyle \frac {21}{5}$


Correct Option: B
Explanation:

Given, $ 8 \times \displaystyle \frac {\frac {5}{24}}{\frac {7}{12}} $

$ \therefore 8 \times \displaystyle \frac {\frac {5 }{24}}{\frac {7}{12}} = 8 \times \frac {5\times 12}{7 \times 24}   $

$=\displaystyle \frac {5 \times 4}{7}$

$= \displaystyle \frac {20}{7} $

$I = \displaystyle \frac{3}{4}\div \frac{5}{6}$ 

$II = 3\displaystyle \div $[($4\displaystyle \div 5$)$\displaystyle \div 6$]
$III = [3\displaystyle \div (4\displaystyle \div 5)]\displaystyle \div 6$
$IV = 3\displaystyle \div 4(5\displaystyle \div 6)$
Select the correct option from the following.

  1. I and II are equal

  2. I and IV are equal

  3. I and III are equal

  4. All are equal


Correct Option: B
Explanation:

$ I=\cfrac{3}{4}\times \cfrac{6}{5}=\cfrac{9}{10}$


$II=3\div \left [ \cfrac{4}{5}\times \cfrac{1}{6} \right ]=3\times \cfrac{15}{2}=\cfrac{45}{2}$

$III=\left [ 3\div \cfrac{4}{5} \right ]\div 6=3\times \cfrac{5}{4}\times \cfrac{1}{6}=\cfrac{5}{8}$

$ IV=3\div 4\times\cfrac{5}{6}=3\times \cfrac{3}{10}=\cfrac{9}{10}$

Hence, $I$ and $IV$ are equal.

The least fraction that must be added to $\displaystyle1\frac{1}{3}\div 1\frac{1}{2}\div 1\frac{1}{9}$  to make the result an integer is:

  1. $\displaystyle\frac{4}{5}$

  2. $\displaystyle\frac{3}{5}$

  3. $\displaystyle\frac{2}{5}$

  4. $\displaystyle\frac{1}{5}$


Correct Option: D
Explanation:

$\displaystyle 1\frac{1}{3}\div 1\frac{1}{2}=\frac{4}{3}\div \frac{3}{2}\div \frac{10}{9}$
$\displaystyle =\frac{4}{3}\times \frac{2}{3}\div \frac{10}{9}=\frac{8}{9}\times \frac{9}{10}=\frac{4}{5}$
$\displaystyle \therefore \frac{1}{5}$ should be added to $\displaystyle \frac{4}{5}$ to make it an integer

The number of positive fractions m/n such that $1/3< m/n < 1$ and having the property that the fraction remains the same by adding some positive integer to the numerator and multiplying the denominator by the same positive integer is

  1. $1$

  2. $3$

  3. $6$

  4. infinite


Correct Option: B
Explanation:

$m, n$ are integer
$1/3 < m/n < 1 $...(i)
$\displaystyle \frac{m + \alpha}{n \alpha} = \frac{m}{n}        n \neq 0$
$\alpha = \displaystyle \frac{m}{m - 1} = +$ve integer
$\therefore m = 2$
Using equation (i)
$n = 3, 4, 5$
$\therefore \displaystyle \frac{m}{n}= \frac{2}{3} , \frac{2}{4}, \frac{2}{5}$