Just multiply the "1.0 m/s" by ' 1 ' a few times. (Remember that a fraction with the same quantity on top and bottom is equal to ' 1 ' .)
(1.0 m/sec) · (1 km/1000 m) · (60 sec/min) · (60 min/hr) =
(1.0 · 60 · 60 / 1,000) (m · km · sec · min / sec · m · min · hr) =
(3,600 / 1,000) (km / hr) =
3.6 km/hr .
