[caw]

In the US, credits are typically by "Credit hours", which I believe is in reference to how much instruction time you have per week. A 3 credit hour class may meet 3x a week for 1 hour, or 2x a week for 1.5hr. So saying 30 credits is the same as saying 30 credit hours, which is 30 "hours" of course work. Wall clock time is higher because you have homework and other stuff, and of course a 3 hour class goes on for at least 12 weeks of instruction.

[gte910h]

At my alma mater, Georgia Tech, they assumed 2-3 out of class hours for each in class hour. So that's 2 terms of 45 hour weeks basically