I think it would be 6 hotdogs per 1 minute. Because that's a rate, and rates can be written as fractions,and fractions are division problems, so 30 divided by 5 is 6.
The notion of a unit rate is how much will happen in a unit of measurement. The question indicates there are 30 hotdogs in a total of 5 minutes, averaging 6 hotdogs per minute, or .1 hotdogs per second. This is done by dividing the total into equal 'chunks' of that unit of time.
The question therefore does not make sense to "not include units".
