Answer:
[tex]r \frac{\text{60 km}}{\text{1000 min}}[/tex]
Step-by-step explanation:
Suppose Kirsten's running rate is r meters per second. This is to be converted to kilometers per minute.
Set up conversion fractions that will get you from
[tex]\frac{\text{m}}{\text{sec}} \rightarrow \frac{\text{km}}{\text{min}}[/tex]
You want to set up fractions so that the m on top is replaced with km and the sec on the bottom is replaced with min.
[tex]\frac{\text{m}}{\text{sec}} \times \frac{\text{km}}{\text{m}} \times \frac{\text{sec}}{\text{min}}[/tex]
To see how the units work, cancel the m on top of the first fraction and the m on the bottom of the second fraction. Do the same with the sec on the bottom of the first fraction and the top of the third fraction. What units are left? km per min!
To finish this, put the appropriate numbers into each fraction.
[tex]\frac{\text{m}}{\text{sec}} \times \frac{\text{1 km}}{\text{1000 m}} \times \frac{\text{60 sec}}{\text{1 min}} = \frac{\text{60 km}}{\text{1000 min}}[/tex]
This is what you multiply Kirsten's rate by, so she runs
[tex]r \frac{\text{60 km}}{\text{1000 min}}[/tex]
