Expert: Josh - 7/28/2003

Question
Hello:

If someone or something can travel 25 feet in 30 seconds, how many miles per hour is this equal to?

Be sure to assign units to the numbers so that I can see how the units cancel throughout the calculation.

I thank you for your assistance and answer.

Answer
Since 1 mile = 5280 feet = 1.6093 kilometre
and   1 hour = 60[sec/min]*60[min/hour] = 3600 seconds

we have 25[foot]/30[second]=

25[foot]*(1/5280)[mile/foot]
----------------------------
30[sec]*(1/3600)[hour/sec]

=(25/5280)/(30/3600) [mile/hour]
=(1/211.2)/(1/120) [mile/hour]
=(1/211.2)*(120) [mile/hour]
=120/211.2[mile/hour]
~=0.5682 mile/hour

Always look up a conversion table if you need to convert between different units. Please do this in the future.
[http://www.dgsgardening.btinternet.co.uk/convert.htm]

Regards.