Answer to Question #139505 in Statistics and Probability for Ella Ssebulime

Question

Weighted Average Grade (missing grade). Suppose that your grade for the class is dependent upon four marking periods (MP1, MP2, MP3, MP4), each worth 20%, a midterm (MT) worth 10%, and a final exam (FE) worth 10%. Also, you have yet to take the final exam, and you want to earn a 90 average for the year. Your grades so far are given below. What score do you need to earn on the final exam in order to obtain a 90 for the year?

Grade/Term MP1 89 MP2 93 MT 85 MP3 88 MP4 94 FE

Answer 1

The weighted average is

$89 \cdot 0.2 + 93 \cdot 0.2 + 85 \cdot 0.1 + 88 \cdot 0.2 + 94 \cdot 0.2 + 0.1 \cdot X =90$

where X is a grade for FE.

$81.3 + 0.1 \cdot X =90$

$0.1 \cdot X =8.7$

$X = 87$

Answer: 87