Answer:
4.44 m/s
Explanation:
Since we want the unit to be in m/s (meter per second), we will be converting from 4 kilometers to meter unit and 15 minutes to second unit.
We know that a kilometer equals to 1000 meters. Multiply both sides by 4:
[tex]\displaystyle{4 \cdot 1 \ \, \sf{km} = 1000 \ \, \sf {m} \cdot 4 }\\\\\displaystyle{4 \ \, \sf{km} = 4000 \ \, \sf {m}}[/tex]
Therefore, 4 kilometers will equal to 4000 meters.
Next, we also know that a minute equals to 60 seconds. Multiply both sides by 15:
[tex]\displaystyle{15 \cdot 1 \ \, \sf{minute} = 60 \ \, \sf {seconds} \cdot 15 }\\\\\displaystyle{15 \ \, \sf{minute} = 900 \ \, \sf {seconds} }[/tex]
Therefore, 15 minutes will equal to 900 seconds.
Now we have the units in meter and second. We will use the formula of speed to find the rate of change in meter/second. The formula of speed is:
[tex]\displaystyle{v = \dfrac{s}{t}}[/tex]
where v is speed, s is distance and t is time. We know that distance is 4000 meters and time is 900 seconds. Substitute in the formula:
[tex]\displaystyle{v = \dfrac{4000 \ \, \sf{meters}}{900 \ \, \sf{seconds}}}\\\\\displaystyle{v = 4.44 \ \, \sf{m/s}}[/tex]
Therefore, her speed is 4.44 m/s
