A university student completed courses worth 3 credits and some courses worth 4 creditsThe student earned a total of 54 credits after completing 15 coursesHow many courses worth 4 credits did the student complete?
Let x be the number of courses worth 4 credits that the student completed.
Since the student completed a total of 15 courses, the number of courses worth 3 credits would be 15 - x.
The total number of credits earned from the courses worth 4 credits is 4x, and the total number of credits earned from the courses worth 3 credits is 3(15 - x).
Therefore, the total number of credits earned by the student is:
4x + 3(15 - x) = 54
4x + 45 - 3x = 54
x + 45 = 54
x = 9
The student completed 9 courses worth 4 credits.