84
Explanation
Step 1
find the ratio
[tex]\text{ratio}=\frac{21\text{ kilometers}}{2\text{ minutes}}=10.5\text{ kilometers per minute}[/tex]
Step 2
let x represents the missing number, the
[tex]\begin{gathered} \text{ratio}=\frac{x\text{ kilometers}}{8\text{ minutes}} \\ \end{gathered}[/tex]
as the ratio is the same
[tex]\begin{gathered} 10.5\text{ kilometer per minute= }\frac{x\text{ kilometers}}{8\text{ minutes}} \\ \\ 10.5=\frac{x}{8} \\ \text{Multiply both sides by 8} \\ 10.5\cdot8=\frac{x}{8}\cdot8 \\ 84.0=x \end{gathered}[/tex]
so, the missing number is 84.
I hope this helps you
