Answer: the rate is (1/8) paintings per week
Explanation:
We usually define the rate as the amount of work done in some unit of time.
In this case, we know that the artist does 1/4 of a painting in 2 weeks, then the rate can be written as:
(1/4)/2 paintings/week = (1/8) paintings/week.
This means that the rate is (1/8) paintings per week, this is the weekly rate at which she works.