a modern airplane flies 18 feet in 2 seconds. what is the airplanes speed in miles per hour rounded to nearest hundreth
(18 * 5280)/(2 * 30 * 60) = ?
Time to learn about dimensional analysis. The units cancel just like numeric factors. Since you can always multiply by 1 without changing things, just use the various values of 1 that cancel the unwanted units.
You want to convert ft/s to mi/hr
So,
18ft/2sec * 1mi/5280ft * 3600sec/hr = 6.13 mi/hr
You can see that PsyDAG tried to do that above, but lost track of some of the factors.
That's a pretty slow plane! But it makes sense, since we all know that 60 mi/hr = 88 ft/s, and this is a lot slower than that. I suspect a typo.