Math CentralQuandaries & Queries


Question from Cody:

if a train travels 400 meters in 30 seconds how many kilometers per hr is it traveling

Ho Cody,

One kilometer is 1000 meters so

\[\mbox{400 meters is } \frac{400}{1000} \mbox{ kilometers.}\]

One hour is 60 minutes and one minute is 60 seconds so one hour is $60 \times 60$ seconds or

\[\mbox{one second is} \frac{1}{60 \times 60} \mbox{ hours.}\]

Hence the train travels

\[\frac{400}{1000} \mbox{ kilometers in }30 \times \frac{1}{60 \times 60} \mbox{ hours.}\]

How far does it travel in one hour?


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