Suppose that you are taking a course that has three exams which count for three-fifths of your grade and a final which counts for two-fifths of your grade. On your first three tests your scores on were 75, 80, and 74. To get an B in the course, you must have an average of at least 80 percent. What is the minimum score you need on the fourth test to get an B for the course? Round your answer to one decimal.
you need
3/5 (75+80+74)/3 + 2/5 x = 80
x = 85.5
8x9 and 8x8 and 8x7 and lastest 8x6
To find the minimum score you need on the fourth test to get a B in the course, we need to calculate the overall average score you need to achieve 80% in the course.
Let's start by calculating the current average score you have for the first three tests.
Add up the scores on the first three tests: 75 + 80 + 74 = 229
Now divide the sum by the number of tests (which is 3 in this case): 229 / 3 = 76.333
So, your current average score for the first three tests is 76.333.
Next, let's calculate the overall average score you need to get a B in the course.
For this, we'll need to consider the weights of the exams. The three tests count for 3/5 or 0.6 of your grade, and the final exam counts for 2/5 or 0.4 of your grade.
Since you need an overall average of at least 80% for a B, we can express that as:
(0.6)(average of the first three tests) + (0.4)(score on the fourth test) = 80
Substituting the values we know, we get:
(0.6)(76.333) + (0.4)(minimum score on the fourth test) = 80
Simplifying the equation:
45.8 + (0.4)(minimum score on the fourth test) = 80
Subtracting 45.8 from both sides:
0.4(minimum score on the fourth test) = 34.2
Now, divide both sides of the equation by 0.4 to isolate the minimum score on the fourth test:
(minimum score on the fourth test) = 34.2 / 0.4
Calculating this value:
(minimum score on the fourth test) = 85.5
Therefore, in order to get a B in the course, you need to score at least 85.5 on the fourth test, rounded to one decimal place.