Alrighty 2 m/s
(2m/s) X (1 km/ 1000 m) X (60s / 1 min) X (60 min / 1 hr) = 7.2 km/hr
Part B:
7.2 X 4 = 28.8
Basically what I am doing is canceling out terms and replacing them with the terms I want. for example: I need to convert meters into kilometers. In my given (2 m/s) meters is on the top and my answer requires that I have km on the top. SO to convert meters into kilometers I have to put meters on the bottom and kilometers on the top.
Hence, why I put (1 km/ 1000 m) km on top (like I want and m on bottom to cancel m). I did the same thing with converting seconds into hours.