A university student completed courses worth 3 credits and some courses worth 4 credits. The student earned a total of 54 credits after completing 15 courses. How many courses worth 4 credits did the student complete? Please show your work.

Answer 1

3 credits x 15 courses = 45 credits

4 credits x x courses = 54 credits

54 - 45 = 9

x = 9/4

x = 2.25

The student completed 2 courses worth 4 credits.

Answer 2

AAAaannndd the bot gets it wrong yet again!

x = # 3-credit courses
y = # 4-credit courses
x+y = 15
3x+4y = 54
so to find y, substitute and solve
3(15-y)+4y = 54
y = 9
so, 6 3-credit courses and 9 4-credit courses
check: 3*6 + 4*9 = 54 ✅