Tag: maths

Quizzes (518) Questions (9324)

Questions Related to maths

Multiple choice maths equations and simple functions further equations solving linear equations with variable on both sides solution of linear equations in one variable

In a family, each daughter has the same number of brothers as she has sisters and each son has twice as many sisters as he has brothers. How many sons are there in the family?

  1. $2$
  2. $3$
  3. $4$
  4. $5$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Let $d$ and $s$ represent the number of daughters and sons respectively.
Then, we have :
$d - 1 = s$ and $2 \left(s - 1\right) = d$.
Solving these two equations, we get: $d = 4$, $s = 3$.

Multiple choice maths equations and simple functions further equations solving linear equations with variable on both sides solution of linear equations in one variable

A number consists of two digits whose sum is $9$. If $27$ is added to the number, its digits are interchanged. Are the given steps to find the number true?
Step $1$: Let the unit's digit be x
Step $2$: Then, ten's digit $=(9-x)$
$\therefore$ number $=10\times (9-x)+x\Rightarrow 90-10x+x=(90-9x)$
Step $3$: Adding $27$ to the number $90-9x$ we get $117-9x$
Step $4$: Number with digits interchanged is $10x+(9-x)=9x+9$
Step $5$: $117-9x=9x+9$ 
Step $6$: Therefore unit's digit$=6$ and ten's digit $=3$
Step $7$: Hence the number $=36$.

  1. Yes

  2. No

  3. Cannot say
  4. Only step $1$ and $2$ are correct
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

All the given steps to find that unknown number are True.
Hence the option A is the correct answer.

Multiple choice maths equations and simple functions further equations solving linear equations with variable on both sides solution of linear equations in one variable

When a number is reduced by $4$, it becomes $80\%$ of itself. Find the number.

  1. $20$
  2. $30$
  3. $40$
  4. $50$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Let the Number be $X$
Number is reduced by $4$ i.e. $X-4$.
Now number becomes $80 \% $ of itself
$X-4 =  80\%  $ of $X$
$ \Rightarrow X-4 = \dfrac{80}{100}\times X$
$ \Rightarrow X-4 = 0.8 X$
$ \Rightarrow 0.2X=4 $
$ \Rightarrow X=20 $
The number is $20$.
Multiple choice maths equations and simple functions further equations solving linear equations with variable on both sides solution of linear equations in one variable

A number is multiplied by $2\displaystyle\frac{1}{3}$ times itself and then $61$ is subtracted from the product obtained. If the final result is $9200$, then the number is __________.

  1. $36$
  2. $63$
  3. $67$
  4. $37$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Let the number is $x$

According to given question, we have
$ x\times \dfrac{7x}{3} -61 = 9200$

$\Rightarrow \dfrac{7x^2}{3}=9261$
$\Rightarrow x^2=9261\times  \dfrac{3}{7}$
$\Rightarrow x^2 =3969$
$\Rightarrow x=\sqrt{3969}$
$\Rightarrow x=63$

Multiple choice maths equations and simple functions further equations solving linear equations with variable on both sides solution of linear equations in one variable

The two consecutive multiples of $3$ whose sum is $51$ are __________.

  1. $24, 27$
  2. $20, 31$
  3. $40, 11$
  4. $25, 26$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Lets say $x$ is the multiple of $3$

Next consecutive multiple of $3$ will be $(x+3)$
Given sum is $=51$
$\Rightarrow x+x+3=51$
$\Rightarrow  2x=48$
$\Rightarrow x=24$
Two consecutive multiples of $3$ are $24,27$.

Multiple choice maths equations and simple functions further equations solving linear equations with variable on both sides solution of linear equations in one variable

$\displaystyle\left(\displaystyle\frac{2}{3}\right)^{rd}$ of a number when multiplied by $\displaystyle\frac{3}{4}$ of the same number make $338$. The number is ___________.

  1. $18$
  2. $24$
  3. $36$
  4. $26$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Let the number is $x$

Thus according to given problem, we have
$\dfrac{2}{3} x\times  \dfrac{3}{4} x= 338$
$x^2=338\times 2$
$x^2= 676=26^2$
$x=26$
Therefore, the number is $26$.

Multiple choice maths equations and simple functions further equations solving linear equations with variable on both sides solution of linear equations in one variable

A number is multiplied by half of itself and then $32$ is added to the product, if the final result is $130$, then find the original number.

  1. $4$
  2. $7$
  3. $5$
  4. $14$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Let the number be $x$

According to given question, we have
$x\times  \dfrac{x}{2} +32=130$

$\Rightarrow \dfrac{x^2}{2}=98$
$\Rightarrow x^2=196$
$\Rightarrow x=14$

Therefore, the number is $14$.

Multiple choice maths equations and simple functions further equations solving linear equations with variable on both sides solution of linear equations in one variable

If $\left(\displaystyle\frac{2}{3}\right)^{rd}$ of a number is $20$ less than the original number, then the number is ___________.

  1. $60$
  2. $40$
  3. $80$
  4. $120$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Let the number is $x$

Therefore, $x-\dfrac{2}{3}x =20$
$\Rightarrow \dfrac{1}{3}x=20$
$\Rightarrow x=60$
Therefore, the  number is $60$.

Multiple choice maths equations and simple functions further equations solving linear equations with variable on both sides solution of linear equations in one variable

A lady reaches her office $20$ minutes late by traveling at a speed of $20$ km/h and reaches $15$ minutes early by traveling at $30$ km/h. By how much time will she be early or late if she travels at $25$ km/h?

  1. $1$ minute early
  2. $5$ minutes early
  3. $1$ minute late
  4. $5$ minutes late
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Let the distance of the office be $x$ km


Time taken at $20 km/hr = \dfrac{x}{20}hrs$

Given that she reaches $\dfrac{20}{60} = \dfrac{1}{3} hrs$ late

Time taken at $30 km/hr = \dfrac{x}{30}hrs$

Given that she reaches $\dfrac{15}{60} = \dfrac{1}{4} hrs$ early

$\therefore \dfrac{x}{20} - \dfrac{x}{30} = \dfrac{1}{3} + \dfrac{1}{4}$

$\Rightarrow x = 35km$

Time taken at $30km/hr = \dfrac{35}{30}\times 60 = 70$ minutes

Time taken at $25 km/hr = \dfrac{35}{25}\times60 = 84$ minutes

So travelling at $25 km/hr$ she reaches $70+15-84 = 1$ minute early

Multiple choice maths equations and simple functions further equations solving linear equations with variable on both sides solution of linear equations in one variable

The average age of $3$ sisters is $15$. If the ages of $2$ sisters are $12$ years and $15$ years, the age of the third sister is-

  1. 21 years

  2. 17 years

  3. 18 years

  4. 16 years
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Let the ages of sisters be $x,y,z$


Given that

$\Rightarrow \dfrac{x+y+z}{3}=15$

$\Rightarrow x+y+z=45$

Given that $x,y=12,15$

$\Rightarrow 12+15+z=45$

$\Rightarrow z=18$

Therefore, age of third sister is $18 years$