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
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?
2 answers
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
https://www.jiskha.com/questions/1821048/a-student-has-scored-84-78-and-86-on-three-100-point-examinations-for-math-class-how
1 answer