Given a basic probability question, what key word(s) make clear
that it is a permutation or combination problem?
Usually there are no "key words" to warn us.
You must call on your "life experience" to interpret the situation.
"Form a committee of 3 people from 12 members."
Does the order of their names make a difference?
No, is the same committee as
This is a Combination.
"Form 3-letter words from the letters
Does the order of the letters make a difference?
Yes, is not the same as
This is a Permutation.
An amusing observation . . .
A combination lock has a set of three numbers used for unlocking.
But the three numbers must applied in a specific order.
So shouldn't it be called a permutation lock?