ASKING FOR HELP,
A STUDENT HAS SCORED 84, 78 AND 86 ON THREE 100 -POINT EXAMINATIONS FOR MATH CLASS. HOW MANY POINTS DOES THE STUDENT NEED TO SCORE ON THE 200-POINT FINAL EXAM, IN ORDER TO GET AN AVERAGE OF 90%, WHICH IS AN A, IN THE COURSE?
Depends if a method of weighted average is used or not
Weighted average:
(84 + 78 + 86 + x)/(100+100+100+200) = 90/100
(248+x)/500 = 90/100
248+x = 450
x = 202
He cannot get a score of 90%, he would need 202/200
so, no way!
method 2
All tests have the same value
(90/100 + 78/100 + 86/100 + x/200)/5 = 90/100
multiply each side by 5
90/100 + 78/100 + 86/100 + x/200 = 450/100
multiply each term by 200
180 + 156 + 172 + x = 900
x = 392
so he must get 392/200 or NOWAY
Asked and answered earlier.
https://www.jiskha.com/questions/1821048/a-student-has-scored-84-78-and-86-on-three-100-point-examinations-for-math-class-how
To find out how many points the student needs to score on the final exam, we can calculate the total points the student has currently earned and subtract it from the total points required for an average of 90%.
First, let's find the total points the student has earned so far. The student scored 84, 78, and 86 on three 100-point examinations.
Total points earned = 84 + 78 + 86 = 248
Now, let's calculate the total points required for an average of 90%. Since the student took three 100-point examinations and a 200-point final exam, there are a total of 500 points available for the entire course.
Total points required for an average of 90% = 90% of 500 = (90/100) * 500 = 450
To find out how many points the student needs to score on the final exam, we subtract the total points earned so far from the points required for an average of 90%:
Points needed on the final exam = Total points required - Total points earned
Points needed on the final exam = 450 - 248 = 202
Therefore, the student needs to score at least 202 points on the 200-point final exam in order to get an average of 90% (an A) in the course.