Tag: maths

Questions Related to maths

Evaluate : $0.75 - 0.0075$.

  1. $0.7405$

  2. $0.7425$

  3. $0.7415$

  4. $0.7525$


Correct Option: B
Explanation:

    $0.7500$
$-   0.0075$
______
    $0.7425$
______
$\therefore$  Required difference $= 0.7425$.

$301.01 - 0.101 = x + 198.01$

  1. $103.119$

  2. $103.101$

  3. $102.901$

  4. $102.899$


Correct Option: D
Explanation:

$x = 301.01 - 0.101 - 198.01$
   $= 301.01 - 198.111 = 102.899$

The simplified value of $\displaystyle\frac{10.24 \div 1.6}{20 - 19.8}$ is

  1. $1.6$

  2. $3.2$

  3. $16$

  4. $32$


Correct Option: D
Explanation:

$\displaystyle\frac { 10.24 }{ 1.6 } = \displaystyle\frac { 102.4 }{ 16 } = 6.4$
$\therefore \displaystyle\frac { 10.24\div 1.6 }{ 20-19.8 } = \displaystyle\frac { 6.4 }{ 0.2 } = \displaystyle\frac { 64 }{ 2 } = 32$

Simplify :$\displaystyle \left ( 0.\overline{1} \right )^{2}\left { 1-9\left ( 0.\overline{16} \right )^{2} \right }$

  1. $\displaystyle \frac{1}{162}$

  2. $\displaystyle \frac{1}{108}$

  3. $\displaystyle \frac{7696}{10{6}}$

  4. $\displaystyle \frac{1}{106}$


Correct Option: B
Explanation:

$\displaystyle \left ( 0.\overline{1} \right )^{2}\left { 1-9\left ( 0.\overline{16} \right )^{2} \right }$


= $\displaystyle \left ( \frac{1}{9} \right )^{2}\left { 1-9\left ( \frac{16-1}{90} \right )^{2} \right }=\frac{1}{81}\left { 1-9\times\left ( \frac{15}{90} \right )^{2}  \right }$

= $\displaystyle \frac{1}{81}\left { 1-9\times \frac{1}{36} \right }=\frac{1}{81}\times \frac{3}{4}=\frac{1}{108}$

Simplify : $[ 0.9 - { 2.3 - 3.2 - 3.2 - ( 7.1- 5.4 - 3.5 ) } ]$

  1. 0.18

  2. 1.8

  3. 0

  4. 2.6


Correct Option: C
Explanation:

$\displaystyle \left [ 0.9-\left { 2.3-3.2-\left ( 7.1-5.4-3.5 \right ) \right } \right ]$


=$\displaystyle \left [ 0.9-\left { 2.3-3.2-\left ( 7.1-8.9 \right ) \right } \right ]$

= $\displaystyle \left [ 0.9-\left { 2.3-3.2-\left ( -1.8 \right ) \right } \right ]$

= $\displaystyle \left [ 0.9-\left { 2.3-3.2+1.8 \right } \right ]$

= $\displaystyle \left [ 0.9-\left { 4.1-3.2 \right } \right ]$

= $\displaystyle \left [ 0.9-0.9 \right ]=0 $

$\displaystyle (0.34\overline{67}+0.13\overline{33})$ is equal to 

  1. $\displaystyle 0.\overline{48}$

  2. 0.4803

  3. $\displaystyle 0.48\overline{01}$

  4. $\displaystyle 0.4\overline{8}$


Correct Option: C
Explanation:

$\displaystyle 0.34\overline{67}+0.13\overline{33}=\frac{3467-34}{9900}+\frac{1333-13}{9900}$


= $\displaystyle \frac{3433}{9900}+\frac{1320}{9900}=\frac{4753}{9900}$

= $\displaystyle \frac{4801-48}{9900}=0.4801 $

Evaluate the expression $\displaystyle 6\frac{1}{4}\times 0.25+0.75-0.3125$

  1. $5.9375$

  2. $4.2968$

  3. $2.1250$

  4. $2$


Correct Option: D
Explanation:

$\displaystyle 6\frac{1}{4}\times 0.25+0.75-0.3125$
$= 6.25 \times 0.25 + 0.75 - 0.3125$
$= 1.5625 + 0.75 - 0.3125$
$= 2.3125 - 0.3125 = 2$

The value of $\displaystyle 0.\overline{2}+0.\overline{3}+0.\overline{4}+0.\overline{9}+0.\overline{39}$ is 

  1. $\displaystyle 0.\overline{57}$

  2. $\displaystyle 1\frac{20}{33}$

  3. $\displaystyle 2\frac{1}{3}$

  4. $\displaystyle 2\frac{13}{33}$


Correct Option: D
Explanation:

$\displaystyle 0.\overline{2}+0.\overline{3}+0.\overline{4}+0.\overline{9}+0.\overline{39}$


= $\displaystyle \frac{2}{9}+\frac{3}{9}+\frac{4}{9}+\frac{9}{9}+\frac{39}{99}$

= $\displaystyle \frac{22+33+44+99+39}{99}$

= $\displaystyle \frac{237}{99}=2\frac{13}{33}$

Simplify $\displaystyle :0.\overline{4}+0.\overline{61}+0.\overline{11}-0.\overline{36}$

  1. $\displaystyle 0.\overline{83}$

  2. $\displaystyle 0.\overline{87}$

  3. $\displaystyle 0.\overline{80}$

  4. $\displaystyle 0.\overline{85}$


Correct Option: C
Explanation:

$\displaystyle :0.\overline{4}+0.\overline{61}+0.\overline{11}-0.\overline{36}=\frac{4}{9}+\frac{61}{99}+\frac{11}{99}-\frac{36}{99}=\frac{4}{9}+\frac{72}{99}-\frac{36}{99}$


$\displaystyle=\frac{4}{9}+\frac{36}{99}=\frac{44}{99}+\frac{36}{99}=\frac{80}{99}=0.\overline{80}$

In a number system the product of 44 and 11 is 3414 The number 3111 of this system when converted to the decimal number system becomes

  1. 406

  2. 1086

  3. 213

  4. 691


Correct Option: A
Explanation:

The product of 44 and 11 is 484
If base is x then 3411
$3x^3+4x^2+1x^1+4x^0=484$
$3x^3+4x^2+x=480$
This equation is satisfy when x=5
then base is 5
In decimal system number 3111 will be  written
$3\times 5^3+1\times 5^2+1\times 5^1+1\times 5^0=406$