Tag: maths

Questions Related to maths

Which of these months does not have $31$ days?

conversion of time time conversion time measurement of time maths

  1. July

  2. March

  3. August

  4. November

Show answer
Correct Option: D
Explanation:

$\Rightarrow$ All the 12 months have 31 or 30 days.

$\Rightarrow$  31 in case of January, March, May, July, august, October, December & 30 in case of April, June, September, November.
$\therefore$  $November$ does not have $31$ days.

How many seconds does an hour has?

conversion of time time conversion time measurement of time maths

  1. $3600$

  2. $600$

  3. $360$

  4. $60$

Show answer
Correct Option: A
Explanation:

As we know, $1$ hour $=60$ minutes
and $1$ minute $=60$ seconds
So, $1$ hour $=60\times 60=3600$ seconds.
Hence, an hour has $3600$ seconds.

At what time between  $1.30\mathrm { pm }$  and $2\mathrm { pm }$  will both the hands of a clock be at right angles?
conversion of time time conversion time measurement of time maths

  1. $4 \dfrac { 6 } { 11 }$

  2. $61 \dfrac { 5 } { 11 }$

  3. $\operatorname { Both } ( A ) & ( B )$

  4. None of these

Show answer
Correct Option: A
Explanation:

The angle between $2$ successive numbers in the clock is $\dfrac{360}{12}=30^{\circ}$

The angle between successive dots is $\dfrac{360}{60}=6^{\circ}$
For one rotation of minutes hand hours hand rotates by $30^{\circ}$
$\implies $ For increase in $1$ minute there is increase of $\dfrac{1}{2}^{\circ}$ for hours hand

At $1.50\text{pm}$
Angle Between hands of clock at $90+\dfrac{50}{2}=115$

For every $1$ min there is a decrease of $\dfrac{11}{2}^{\circ}$

For every $x$ min there is a decrease of $25^{\circ}$

$\implies x=\dfrac{25\times 2}{11}=4\dfrac{6}{11}$min

So at $4\dfrac{6}{11}$ pm the hands are perpendicular to each other.

If a clock strikes $12$ in $33$ seconds, it will strike $6$ in how many seconds?

conversion of time time conversion time measurement of time maths

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

  2. $15$

  3. $12$

  4. $22$

Show answer
Correct Option: B
Explanation:

In order to strike 12 there are 11 intervals of equal time = $\displaystyle \frac{33}{11}$ = 3 seconds each
Therefore to strike 6 it has 5 equal intervals, it requires 5 $\displaystyle \times $ 3 =15 sec.

$5$ hour $=$ ________ minutes.

conversion of time time conversion time measurement of time maths

  1. $60$

  2. $300$

  3. $120$

  4. $600$

Show answer
Correct Option: B
Explanation:

As we know, $1$ hour $=60$ minutes
So, $5$ hours $=5\times 60=300$ minutes.
Hence, $5$ hours $=300$ minutes.

A boat travels upstream from $B$ to $A$ and down stream from $A$ to $B$ in $3$ hours. If the speed of the boat in still water is $9\ km/hr$ and the speed of the current is $3\ km/ hr$, then the distance (in km) between $A$ and $B$ is

conversion of time time conversion time measurement of time maths

  1. $12$

  2. $8$

  3. $6$

  4. $4$

Show answer
Correct Option: A
Explanation:

Let the distance between $A$ and $B$ be $x$ km.
Upstream speed $= 9 - 2 = 6\ kmph$
Downstream speed $= 9 + 3 = 12\ kmph$
$\dfrac {x}{6} + \dfrac {x}{12} = 3\Rightarrow \dfrac {2x + x}{12} = 3\Rightarrow 3x = 36 \Rightarrow x = 12\ km$.

A mapping $f:N\rightarrow N$ where N is the set of natural numbers is defined as 
$ f\left( n \right) =\left{ { n }^{ 2 },for\quad n\quad odd\ 2n+1,for\quad n\quad even \right \$ .For $n\quad \Box \quad N$.Then f is

conversion of time time conversion time measurement of time maths

  1. Surjective but not injective

  2. Injective but not surjective

  3. Bijective

  4. Neither injective nor surjective

Show answer
Correct Option: D
Explanation:

As $f(3)=f(4)=9$
we can say that function is not one-one and $y=2$ does not exists.we can say that function is not onto. Therefore option D is correct.

A speed of $14$ metres per second is the same as:

conversion of time time conversion time measurement of time maths

  1. $28 \ \mathrm { km } / \mathrm { hr }$

  2. $46.6 \ \mathrm { km } / \mathrm { hr }$

  3. $ 50.4 \ \mathrm { km } / \mathrm { hr }$

  4. $ 70 \ \mathrm { km } / \mathrm { hr }$

Show answer
Correct Option: C
Explanation:

$Speed\>=\>14\>\dfrac{m}{s}$

$=14\dfrac{\dfrac{1km}{1000}}{\dfrac{1hr}{3600}}$


$=\dfrac{14\cdot3600}{1000}\dfrac{km}{hr}=50.4\>\dfrac{km}{hr}$

What unit would you use to measure water?

conversion of time time conversion time measurement of time maths

  1. Hectare

  2. Litre

  3. Gram

  4. Metre

Show answer
Correct Option: B
Explanation:

Hectare and metre are used to measure distances while gram is used to measure mass, and water is measured in terms of volume which is measured as litre.

Which of the followinng book was written by Bhaskaracharya at the age of $36$ years?

mathematicians and their contribution history of mathematics maths

  1. Aryabhatiya

  2. Leelavati

  3. Siddhant Shiromany

  4. Khand Khadya

Show answer
Correct Option: C
Explanation:

 Bhaskaracharya composed the Siddhanta shiromany when he was $36$ years old.