Tag: conversion of time

Questions Related to conversion of time

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

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

  2. $15$

  3. $12$

  4. $22$


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.

  1. $60$

  2. $300$

  3. $120$

  4. $600$


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

  1. $12$

  2. $8$

  3. $6$

  4. $4$


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

  1. Surjective but not injective

  2. Injective but not surjective

  3. Bijective

  4. Neither injective nor surjective


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:

  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 }$


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?

  1. Hectare

  2. Litre

  3. Gram

  4. Metre


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.