Answer:
2 2/3 projects
Explanation:
First disect the statement.
2/3 of a project in 1/4 of an hour.
This means that she does not completely finish grading a project in a quarter hour.
We want to know how much she gets done in one whole hour, however all we know is how much she gets done in 1/4 of that time. Luckily, 1/4 times 4 is a whole hour. Since 2/3 of a project gets done in 1/4 that means if we multiply 2/3 by four we should also get how much she completes in one hour.
2/3 x 4 = 8/3
8/3 = 2 2/3 projects
You can also right these as ratios:
(2/3)/(1/4) = x/1
x = 8/3