fyi, this is the chemistry section so
convert each
30 meters per second
kilometers per hour
1000 meters=1 kilometers
60 seconds=1 hour so
30 meters=30/1000 kilometers=3/100=0.03 kilomiters
1 second=1/60 hours
0.03/(1/60)
make the bottom =1
multiply the whole fraction by (60/1)/(60/1)
1.8/(60/60)=1.8/1=1.8km/1h
the answer is 1.8km/h