Question

A car travels at \[45km\] per hour. How much time will it take to cover \[90km\] ?
1. $1$ hour
2. \[2\] hours
3. \[\;3\] hours
4. \[10\] hours

Answer 1

Hint: First, we shall analyze the given information. It is given that a car travels at \[45km\]per hour. We are asked to calculate the time required by the car to cover\[90km\].
It can be understood that the values of speed and distance are given in the question.
That is, it is given that speed $ = $\[45\dfrac{{Km}}{h}\]
Distance$ = $ $90km$
We need to just substitute the above values in the given formula.
Formula used:
 The formula to obtain the speed is as follows.
\[Speed = \dfrac{{Distance}}{{Time}}\]
Since we are asked to calculate the time taken, we shall change the above formula as follows.
$Time = \dfrac{{Distance}}{{Speed}}$

Complete step by step answer:
It can be understood that the values of speed and distance are given in the question.
That is, it is given that speed $ = $\[45\dfrac{{Km}}{h}\]
Distance $ = $$90km$
We are asked to calculate the time required by the car to cover\[90km\].
Now, using the formula, we have,
$Time = \dfrac{{Distance}}{{Speed}}$
Time = \[\dfrac{{90\,{\text{km}}}}{{45\,{\text{kmph}}}}\]
After some simplification by dividing the terms we get
Time \[ = 2\]hours
Therefore, it will take two hours for the car to cover \[90km\] which is the required answer.

So, the correct answer is “Option 2”.

Note: If required, first we need to convert the given units into our required units. Suppose we are asked to calculate the distance, we just convert the formula for our convenience.
That is,
\[Speed = \dfrac{{Distance}}{{Time}}\]into
\[Speed \times Time = Dis\tan ce\]
The SI unit of speed is $m{s^{ - 1}}$ .
The SI unit of time is $s$ .
The SI unit of distance is $m$ .
The long distances are measured in kilometers.
Therefore, here in this question, it will take two hours for the car to cover \[90km\].