Question

A boy running at an average speed of 4 km/hr, reaches school from his home in $1/2$ hr. The distance of the school from his home is?
(A) 2 Km
(B) 8 Km
(C) 4Km
(D) 6Km

Answer 1

Hint: This could be simply solved by simply getting the distance over that duration. The average speed is the distance per time ratio.
Formula used: Here, we will use the basic formula of speed, distance and time:
${{\text{V}}_{{\text{avg}}}}{\text{ = }}\dfrac{{\text{D}}}{{\text{T}}}$
Here, ${{\text{V}}_{{\text{avg}}}}$ is the mean speed of the boy
${\text{D}}$ is the total distance travel
$T$ is the travel time

Complete step by step answer:
We will start by considering the total distance to be${\text{d}}$,
For the first third of the distance:
${{\text{v}}_{\text{1}}}{\text{ = 4kmph}}$
${{\text{t}}_{\text{1}}}{\text{ = 1/2 hr}}$
Applying the formula we get:
Now the mean speed over distance:
Distance = speed * time
Thus, the entire distance is 2Km.

So, the correct option is A.

Additional Information: Distance is a scalar measure of the interval between two locations measured along the actual path connecting them. Displacement is a vector measure of the interval between two locations measured along the shortest path connecting them. Speed is a scalar quantity that refers to "how fast an object is moving." Speed can be thought of as the rate at which an object covers distance. The first scientist to measure speed as distance over time was Galileo.

Note: It should always be kept in mind that there is a difference between speed and velocity. Just as distance and displacement have distinctly different meanings, same is the situation between speed and velocity. Velocity is a vector quantity that refers to the rate at which an object changes its position whereas speed is a scalar quantity that refers to how fast an object is moving. Velocity gives us a sense of direction whereas speed does not give any sense of direction.