To receive a c grade, a student must average more than 77 but less than or equal to 85. if ethan received a c in the course and had five grades of 74, 78, 76, 67, and 85 before taking the final exam, what were the possible grades for his final if there were 100 points possible? (assume all six grades are weighted equally and let x represent the unknown score.)

So for his mark will be in between 82 to 130 for C grade

Step-by-step explanation:

We have given that for C grade the minimum average mark should be 77 and maximum average mark should be 85

There are 6 subjects

So total minimum mark = 6×77 =462

And total maximum mark = 85×6 =510

He has five grades as 74,78,76,67,85

So sum of five grades = 74+78+76+67+85=380

Let he get x marks in 6th

So for minimum mark in 6th grade  x+380 = 462

x = 462-380=82

For maximum mark x+380=510

x = 510-380 =130

So for his mark will be in between 82 to 130 for C grade