a) We convert per minute to per hour so we multiply it by 60 to get:
=> 504km/h
b) We convert per second to per hour so we multiply it by 3600 to get:
=> 1134000m/h
=> We then convert meters into km to get:
=> 1134km/h
c) We convert per minute to per hour so we multiply it by 60 to get:
=> 14520m/h
=> Now we convert meters into km once again so we get:
=> 14.52km/h
d) We convert per second to per hour so we multiply it by 3600 to get:
=> 450000cm/h
=> We now convert cm into km which means we divide it by 100,000
=> 4.5km/h