Tag: how many in all?

Questions Related to how many in all?

$45 \% \text { of } 1500 + 35 \% \text { of } 1700 = ? \% \text { of } 3175$

maths calculating and mental strategies 3 finding percentage of a number how many in all? problems on percentage

  1. 30

  2. 35

  3. 40

  4. 50

Show answer
Correct Option: C
Explanation:

$45\%$ of $1500$ is given as 

$\dfrac{45}{100}\times 1500$

$\implies 45\times 15=675$

$35\%$ of $1700$ is given as 

$\dfrac {35}{100}\times 1700$

$\implies 35\times 15=595$

Total is $675+595=1270$

Let the percent be $x$ 

$\implies \dfrac x{100}\times 3175=1270$

$\implies x=\dfrac {1270}{3175}\times 100$

$\implies x=40\%$ 

To get $55\%$ of a number, the number should be multiplied by 

maths calculating and mental strategies 3 finding percentage of a number how many in all? problems on percentage

  1. $\dfrac {11}{20}$

  2. $3.5$

  3. $\dfrac {7}{50}$

  4. $0.035$

Show answer
Correct Option: A

Evaluate approximate value of $15.2$% of $726\times 12.8$% of $643.$

maths calculating and mental strategies 3 finding percentage of a number how many in all? problems on percentage

  1. $9562$

  2. $9324$

  3. $9082$

  4. $9710$

Show answer
Correct Option: C
Explanation:

the approximate value of $15.2\%$ of $726 \times 12.8\%$ of $643=$ 

$\dfrac{15.2}{100}\times 726\times \dfrac{12.8}{100}\times 643$
$=9082\cdot 411$
$=9082$ (approx)

In an examination in which full marks were $800$. $A$ gets $20\%$ more than $B$, $B$ gets $20\%$ more than $C$ and $C$ gets $15\%$ less than $D$. If $A$ got $576$, what percentage of full marks did $D$ get? ( approximately)?

maths calculating and mental strategies 3 finding percentage of a number how many in all? problems on percentage

  1. $45.7$

  2. $51.2$

  3. $58.8$

  4. $61.7$

Show answer
Correct Option: C
Explanation:

Given, $\displaystyle A=\frac{120}{100}B$,

$B=\dfrac{120}{100}C$ and 
$C=\dfrac{85}{100}D$
$\Rightarrow B=\dfrac{5}{6}A,C=\dfrac{5}{6}B,D=\dfrac{20}{17}C$
$\displaystyle \Rightarrow  B=\frac{5}{6}\times 576=480$
$\Rightarrow C=\dfrac{5}{6}\times 480=400$
$\Rightarrow D=\dfrac{20}{17}\times 400=\dfrac{8000}{17}$
So, required percentage $\displaystyle =\left ( \frac{8000}{17}\times \frac{1}{800}\times 100 \right )\%=58.82\%$

15 litres of a mixture contain 20% milk and the rest water. If 3 litres of water be mixed in it, the percentage of milk in the new mixture will be ..............

maths calculating and mental strategies 3 finding percentage of a number how many in all? problems on percentage

  1. 17%

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

  3. 18$\frac{1}{2}$%

  4. 15%

Show answer
Correct Option: B
Explanation:

15 litres of a mixture contain 20% milk
So, milk=15*20/100=3 litres
water=15-3=12 litres
3 litres of water is mixed, so 
 new 18 litres of mixture has 15 litres of water and 3 litres of milk
So, percentage of milk= quantity of milk*100/total mixture
$M$ %$=3*100/18$
$=100/6=16\frac { 2 }{ 3 }$ %
Answer (B) 16$\frac{2}{3}$%


Due to an increase of 30% in the price of eggs. 3  eggs are available for rs. 7.80. The present rate of eggs per dozen is ____.

maths calculating and mental strategies 3 finding percentage of a number how many in all? problems on percentage

  1. Rs. 8.64

  2. Rs. 8.88

  3. Rs. 9.36

  4. Rs.10.40

Show answer
Correct Option: C
Explanation:

Given cost of 3 eggs are Rs 7.80 then cost of one dozen eggs are
=$7.80\times \frac{12}{3}=31.20$Rs
When cost increase 30% Then cost increase on one dozen eggs are=$\times \frac{31.20\times30}{100}=9.36$

What percentage of a day is six hours and 45 minutes?

maths calculating and mental strategies 3 finding percentage of a number how many in all? problems on percentage

  1. 7.218%

  2. 8.3%

  3. 28.125%

  4. None of these

Show answer
Correct Option: C
Explanation:

A day is 24hrs.
 six hours and 45 minutes=
$6\frac { 45 }{ 60 } =6\frac { 3 }{ 4 } =\frac { 27 }{ 4 } Hrs$
So, % of a day=
$=\frac { 27 }{ 4*24 } \times 100$
$=\frac { 27 }{ 4*24 } \times 100=28.13%$
Answer (C) 28.125%

Which is the greatest ?

maths calculating and mental strategies 3 finding percentage of a number how many in all? problems on percentage

  1. $\dfrac{50}{3}\%$

  2. $\dfrac{2}{15}$

  3. $0.17$

  4. $6\%$

Show answer
Correct Option: C
Explanation:

Option A$\Rightarrow \begin{pmatrix}\dfrac{50}{3}\end{pmatrix}\times\begin{pmatrix}\dfrac{1}{100}\end{pmatrix}=\dfrac{1}{6}=0.166$
Option B $\Rightarrow \dfrac{2}{15}=0.133$
Option C $\Rightarrow 6\%=\dfrac{6}{100}=0.06$
Clearly $\Rightarrow 0.17$ is greater

Mary expected to $120$ people for her wedding, but only $60$ people appeared. What was the percentage error?

maths calculating and mental strategies 3 finding percentage of a number how many in all? problems on percentage

  1. $75\%$

  2. $25\%$

  3. $55\%$

  4. $100\%$

Show answer
Correct Option: D
Explanation:

To Calculate percentage error:
Expected number of people = $120$
Actual number of people attended = $ 60$

Percentage of error
=$\dfrac{Absolute value - exact value}{Exact value} \times 100$

 = $ \dfrac{120 - 60}{60} \times{100}$

= $ 100 $ %

Tom expected to $100$ people for his marriage party, but only $80$ people appeared. What was the percentage error?

maths calculating and mental strategies 3 finding percentage of a number how many in all? problems on percentage

  1. $75\%$

  2. $25\%$

  3. $55\%$

  4. $65\%$

Show answer
Correct Option: B
Explanation:

Given, Absolute value $=100$, exact value $=80$

We know, percentage error $=$ $\left | \dfrac{Absolute \space\ value - exact \space\ value}{exact\space\ value} \right |\times 100$%
$=$ $\left | \dfrac{100 - 80}{80} \right |\times 100$%
$=$ $\left | \dfrac{ 20}{80} \right |\times 100$%
$=$ $\left | 0.25\right |\times 100$%
$= 25\%$