Q:

Grading Scale 2 has the following weights- Tests- 60% Quiz- 15% Homework- 10% Final Exam- 15% What do you need to score on the Final Exam to make an 78 in the class if your grades are- Show steps. Test Grades- 85 Quiz- 87 Homework- 68 Final Exam- ??a. 85(60) + 87(15) + 68(10) + X(15) = 78 X = 49.33b. 85(6.0) + 87(1.5) + 68(1.0) + X(1.5) = 78 X = 53.62c. 85(.60) + 87(.15) + 68(.10) + X(.15) = 78 X = 47.67 d. 85(.60) + 87(1.5) + 68(.10) + X(1.5) = 78 X = 35.59

Accepted Solution

A:
Answer: Β  c. 85(.60) + 87(.15) + 68(.10) + X(.15) = 78; X = 47.67Step-by-step explanation:The weighted average is the sum of products of score and weight. Choice C has the percentage weights properly expressed as decimal values. ___The other equations could work if the final score of 78 were weighted by the corresponding equivalent of 100%. (X is wrong in the other choices as well.)__The attachment shows the "work". Given that choice C is the only correct equation, we presumed that the value of X was correct. The equation solver confirms this. If you want to do it by hand, compute the sum of products, subtract that sum, then divide by 0.15. Β  X = (78 -70.85)/.15 = 7.15/.15 = 47 2/3