Question

The speed of a bus is 24km/hr. How much distance will it travel in 12 seconds?
(A) 160 m
(B) 100 m
(C) 120 m
(D) 80 m

Answer 1

Hint:
Given problem is based on the relationship between speed, time and distance. We will first convert the given unit into SI units of speed, that is we have to convert km/hr into m/sec. We will then use the formula for distance speed and time to find the required distance.

Formula used:
We will use the formula \[d = s \times t\], where \[d\] is the distance, \[s\] is the speed and \[t\] is the time taken by the object to cover the distance.

Complete step by step solution:
Before we apply the given formula to solve the given question, we need to convert the unit of speed into its SI unit.
\[s = 24\] km/hr
\[ \Rightarrow s = \dfrac{{24 \times 1000}}{{60 \times 60}}\] m/s
Now we have to find the distance traveled by the bus in 12 seconds, thus we can find the distance traveled by the bus in 12 seconds by substituting the given information in distance-time-speed formula.
Therefore by substituting values of speed and time in the formula we get,
\[d = s \times t\]
\[ \Rightarrow d = \dfrac{{24 \times 1000}}{{60 \times 60}} \times 12\]
Simplifying the terms, we get
\[d = 80m\]
Therefore, the bus will travel 80 m distance in 12 seconds.

Hence option (D) is the correct option.

Note:
Speed is defined as the distance covered per unit time. Its SI unit is meter per second\[\left( {m/s} \right)\]. While doing any mathematical operation we need to keep all the units of all the terms same. If the units are not the same then we will get the wrong answer. We cannot do mathematical operations on terms until and unless they have the same units.