Jack walks with a pace of #5# kilometers per hour. We calculate the distance Jack has walked with the formula #\orange{s} = 5 \cdot \blue{t}#.
Here the #\orange{\text{distance}}# is denoted in kilometers with the variable #\orange{s}# and the #\blue{\text{time}}# is denoted in hours with the variable #\blue{t}#. Using this formula, we can calculate the distance #\orange{s}# for different values of time #\blue{t}#.

If Jack walks for #\blue{2}# hours, #\blue{t}=\blue{2}#.
We get #\orange{s}= 5 \cdot \blue{2} = \orange{10}#, so Jack has walked #\orange{10}# kilometers.
If Jack walks for #\blue{4}# hours, #\blue{t}=\blue{4}#.
We get #\orange{s}= 5 \cdot \blue{4} = \orange{20}#, so Jack has walked #\orange{20}# kilometers.

The formula:

\[\orange{s} = 5 \cdot \blue{t} \]

If #\blue t=\blue 2#, then #\orange{s}= 5 \cdot \blue{2} = \orange{10}#

If #\blue t=\blue 4#, then #\orange{s}= 5 \cdot \blue{4} = \orange{20}#