SOLUTION: Sam must have an average of 70 or more in his summer course to obtain a grade of C. His first three test grades were 75, 63, and 68. Write an inequality representing the score that

Algebra ->  Equations -> SOLUTION: Sam must have an average of 70 or more in his summer course to obtain a grade of C. His first three test grades were 75, 63, and 68. Write an inequality representing the score that      Log On


   

Question 96438: Sam must have an average of 70 or more in his summer course to obtain a grade of C. His first three test grades were 75, 63, and 68. Write an inequality representing the score that Sam must get on the last test to get a C grade.
Found 2 solutions by checkley71, jenna1026:
Answer by checkley71(8403) About Me  (Show Source):
You can put this solution on YOUR website!
(75+63+68+x)/4>70
(206+x)/4>70
4*70<206+x
280-206 74 proof
(75+63+68+74)/4>70
280/4>70
70>70

Answer by jenna1026(3) About Me  (Show Source):
You can put this solution on YOUR website!
average = (score1+score2+score3+score4)/4
We need average to be 70 or more:
70 <= (75+63+68+s)/4
70 <= (206+s)/4
Distribute:
70 <= 51.5 + s/4
Subtract 51.5:
18.5 <= s/4
Multiply by 4:
74 <= s
Check:
(75+63+68+74)/4 = 70