Tag: maths

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Questions Related to maths

Multiple choice maths percentages finding one number as percentage of another money and metric measures as percentage expressing one quantity as a percentage of another

If $p _1\%$ of number $N _1$ is equal to $p _2\%$ of number $N _2$, what percent of $N _1$ is $N _2$?

  1. $\displaystyle\frac{100p _1}{p _2}$
  2. $\displaystyle\frac{100p _2}{p _1}$
  3. $\displaystyle\frac{p _1}{p _2}$
  4. $\displaystyle\frac{p _2}{p _1}$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

$\displaystyle\frac{p _1}{100}\times N _1=\frac{p _2}{100}\times N _2$

$\displaystyle\frac{N _1}{N _2}=\frac{p _2}{p _1}$, $\displaystyle N=\frac{p _2}{p _1}\times N _2$

Percent of $\displaystyle N _1=\left(\frac{p _2}{p _1}\times100\right)\%$ of $N _2$

Percent of $\displaystyle N _2=\left(\frac{p _2}{p _1}\times100\right)\%$ of $N _1$

Multiple choice maths percentages finding one number as percentage of another money and metric measures as percentage expressing one quantity as a percentage of another

The value of a machine is Rs. $6,250$. It decreases by $10$% during the first year, $20$% during the second year and $30$% during the third year. What will be the value of the machine after $3$ years?

  1. Rs. $2,650$
  2. Rs. $3,050$
  3. Rs. $3,150$
  4. Rs. $3,510$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Value after $1^{st}$ year $=6250-\dfrac {10}{100}\times 6250$
$=5625\ Rs$
Value after $2^{nd}$ year $=5625-\dfrac {20}{100}\times 5625=\dfrac {80}{100}\times 5625$
$=4500\ Rs$
Value after $3^{rd}$ year $=4500-\dfrac {30}{100}\times 4500=\dfrac {70}{100}\times 4500$
$=Rs\ 3150$


Multiple choice maths percentages finding one number as percentage of another money and metric measures as percentage expressing one quantity as a percentage of another

A spider climbed $62\cfrac{1}{2}$% of the height of the pole in one hour and in the next hour it covered $12\cfrac{1}{2}$% of the remaining height. If pole's height is $192m$, then the distance climbed in second hour is:

  1. $3m$
  2. $5m$
  3. $7m$
  4. $9m$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

First hour: 62.5% of 192m = 120m. Remaining height: 192 - 120 = 72m. Second hour: 12.5% of 72m = (1/8) * 72 = 9m.

Multiple choice maths percentages finding one number as percentage of another money and metric measures as percentage expressing one quantity as a percentage of another

In an examination in which full marks were $500$. $A$ got $25$% more than $C$, $C$ got $20$% less than $D$. If $A$ got $360$ marks. What percentage of full marks was obtained by $D$?

  1. $72$%
  2. $80$%
  3. $50$%
  4. $60$%
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
given,full marks in the examination are $500$
A got $360$ marks  
A got $25\%$ more than $C$.
let the marks of $C$ be $'x'$ then, 
$x+\dfrac{25}{100}\times x=360$ 
$\dfrac{5x}{4}=360$
$x=288$
 so,$C$ got $288$ marks . 
given,$C$ got $20\%$ less than $D$ let the marks of $D$ be $'y'$ then,
 $y-\dfrac{20}{100}\times y=288$
 $\dfrac{4y}{5}=288$
$y=360$
 so,$D$ got $360$ marks percentage of full marks obtained by $D$ $=\dfrac{360}{500}\times 100$
$=72\%$
Multiple choice maths percentages finding one number as percentage of another money and metric measures as percentage expressing one quantity as a percentage of another

Tulsiram's salary is $20$% more than that of Kashyap. If tulsiram saves RS. $720$ which is $4$% of his salary, then Kashyap's salary is

  1. Rs. $15,000$
  2. Rs. $12,000$
  3. Rs. $10,000$
  4. RS. $22,000$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

$Salary\quad of\quad Tulsiram$

$ =Rs\quad \dfrac { 720 }{ 4 } \times 100$

$=Rs\quad 18,000$

$Salary\quad of Kashyap\quad $

$=18000\times \dfrac { 100 }{ 120 } $

$ =Rs.15000$

Multiple choice maths percentages finding one number as percentage of another money and metric measures as percentage expressing one quantity as a percentage of another

In two successive years, $80$ and $60$ students of a school appeared at the final examination, of which $60$% and $80$% passed respectively. The average rate of students passed (in percent) is:

  1. $68$%
  2. $68\cfrac{4}{7}$%
  3. $32$%
  4. $36$%
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Total students = 80 + 60 = 140. Passed in year 1: 60% of 80 = 48. Passed in year 2: 80% of 60 = 48. Total passed = 48 + 48 = 96. Average rate = (96 / 140) * 100 = 960/14 = 480/7 = 68 4/7%.