Math
posted by Katherine .
In Wilbur's math class, his grade is based on the average score of six tests, each worth 100 points. Wilbur always worries about his grade. He knows that his average on the four first tests is 88.5. What is the lowest average he could get on his next two tests and still average 90 overall...
please help me i am very confused.....
i need the formula

4 * 88.5 = 354 Total points so far
600 * 0.9 = 540 Total possible for 6 tests
540  354 = 186
186/2 = 91 average on the next two tests 
can i get the formula...please
this is what i got.....
the formula is (88.5 + x + y) divide 3=90
90 * 3 =270
so then (88.5 + 91.5 + 90)=270 /3=90
90*3=270 
I don't understand your formula. But you didn't get an answer for your problem.

But the total average has to be 90 not 91 . So we are right , right ?

The total average must be 90. But Wilbur only has 88.5 average at this point. His average grade on the next two tests must be more than 90 for his overall average to be 90.

no it doesnt . Because if you add 88.5+90+91.5 you get 270 and then you divide 3 you get 90.

I'm sorry you didn't understand my explanation. I averaged grades for 32 years in my teaching career and should know what I'm talking about. You cannot bring up an 88.5 average to 90 with only a couple of 90 test scores.
Please sit down with your teacher to have him/her explain this problem to you. 
Ok i don't understand your formula either. Im sorry, but thankyou anyways. OKAY !!!!

Use The following equation:n 2x+4(88.5)/(6)=90. Solve for x.
x=93 
IDK

Why multiple by 0.9???

I got 94
Im a bad teacher 
You multiply by .9 since that in percentage is 90%. He wants a total average of 90% for his remaining tests. The answer is 91.

I got 93
Respond to this Question
Similar Questions

Statistics
In your biology class, your final grade is based on several things: a lab score, score on two major tests, and your score on the final exam. There are 100 points available for each score. However, the lab score is worth 25% of your … 
8th grade
At Smart Middle School students are required to take 7 classes each grading period. At the end of each grading period a student is assigned a final grade (A, B, C, D or F) for each class for the grading period. A studentâ€™s overall … 
math
At Smart Middle School students are required to take 7 classes each grading period. At the end of each grading period a student is assigned a final grade (A, B, C, D or F) for each class for the grading period. A studentâ€™s overall … 
math
In your biology class, your final grade is based on several things: a lab score, scores on two major tests, and your score on the final exam. There are 100 points available for each score. However, the lab score is worth 16% of your … 
Statistics
In your biology class, your final grade is based on several things: a lab score, scores on two major tests, and your score on the final exam. There are 100 points available for each score. However, the lab score is worth 15% of your … 
Pre Algebra
In Wilbur's math class, his grade is based on the average score of six tests, each worth 100 points. Wilbur always worries about his grade. He knows that his average on the first four tests is 88.5. What is the lowest average he could … 
Algebra
In his mathematics class, John has taken 3 tests, each worth 20% of his total grade. His grades on those tests were 92%,83%,and 85%. He has an 100% average on his homework, worth 10% of his grade. All that remains is a final exam worth … 
Math
In your class, you have scores of 73,85,76, and 92 on the first four of five tests. To get a grade of Upper C, the average of the first five tests scores must be greater than or equal to 70 and less than 80. a) Solve an inequality … 
Math Help
In three math tests, you have scored 91,95 and 88 points. You are about to take your next test. Suppose you want to have an average score of at least 90 points after all four tests. Explain a method you could use to find the score … 
Math
In math class, a student has an average grade of 85% for five tests so far. What grade must that student earn on the next test to reach an average grade of 90% for all six tests?