Question

A car covers a distance of 5 km in 5 mins, its average speed is equal to :
A. 1 km/h
B. 5 km/h
C. 60 km/h
D. 120 km/h

Answer 1

Hint: To find the average speed for the car to cover the distance of 5 km, we will divide the value of the distance by that of the time travelled, now to find the velocity in terms of \[km/hr\], we need to convert the time from minute to hour by dividing it by 60 and the formula for the speed is:
\[\text{Speed = }\dfrac{\text{Distance}}{\text{Time}}\]

Complete step by step answer:
The distance travelled by the car in km is given as \[5\text{ }km\].
The time taken to cover the distance of \[5\text{ }km\]is \[5\text{ }min\].
Now to convert the time from minute to hour is given by dividing the minute value by \[60\]. Hence, the minute value is:
\[\Rightarrow \dfrac{5}{60}=\dfrac{1}{12}h\]
Now using the time, distance and speed formula, we find the value of the speed in terms of km/hr as:
\[\text{Speed = }\dfrac{\text{Distance}}{\text{Time}}\]
Placing the value of distance and time in the above formula, we get the value of the speed as:
\[\Rightarrow \text{Speed = }\dfrac{5\text{ }km}{\dfrac{1}{12}hr}\]
\[\therefore \text{Speed = }60\text{ }km/hr\]
Therefore, the value of the speed of the car moving a distance of 5 km is given as \[60\text{ }km/hr\].

Note:
Another method to find the speed is by converting the distance from \[5km\] to \[5000m\] and time from minute to seconds as \[5\min \] to \[5\times 60=300\text{ seconds}\], then using the formula of the speed and its value as:
\[\text{Speed = }\dfrac{\text{Distance}}{\text{Time}}\]
Placing the value of distance and time as \[5000m\] and \[5\min \] respectively. The value of the speed in terms of \[m/\sec \] is:
\[\text{Speed = }\dfrac{\text{5000}}{300}\]
\[\Rightarrow \text{Speed = }\dfrac{\text{5000}}{300}\text{ }m/s\]
Now to find the speed in terms of \[km/h\] from \[m/s\], we will multiply the speed by \[\dfrac{18}{5}\] to get the speed in terms of \[km/h\] unit.
\[\Rightarrow \text{Speed = }\dfrac{\text{5000}}{300}\times \dfrac{18}{5}\]
\[\Rightarrow \text{Speed = }60\text{ }km/hr\]