Question 1016647
We have {{{10mi/30min}}} and wish to convert to {{{mi/hr}}}

up top, the numerator, we are all set. To cancel min in the denominator, and replace with hours, we will multiply by {{{min/hr}}} but specifically {{{60min/hr}}} as that's the ratio between these units. 


{{{(10mi/30min)(60min/hr)=(20mi/hr)}}}

Note, this process is called dimensional analysis, and can be used for a long chain of calculations. Say, feet/second to miles per year, for example. The setup is important because it keeps the units correct. Multiply by 1hr/60min above, by mistake, and you'll see minutes don't cancel, but you have hr^2 in the denominator. Pay attention to the units, and you won't make that mistake.