SOLUTION: Lisa has an average of 83 in her first four examinations. What should her average score be in the next two examinations be if she aims to have an average of 86?
the choices are:
Algebra ->
Percentage-and-ratio-word-problems
-> SOLUTION: Lisa has an average of 83 in her first four examinations. What should her average score be in the next two examinations be if she aims to have an average of 86?
the choices are:
Log On
Question 498213: Lisa has an average of 83 in her first four examinations. What should her average score be in the next two examinations be if she aims to have an average of 86?
the choices are:
the answer is 92 but i don't know how to solve for it Answer by htmentor(1343) (Show Source):
You can put this solution on YOUR website! Lisa has an average of 83 in her first four examinations. What should her average score be in the next two examinations be if she aims to have an average of 86?
=================================
Let s1 = the 1st exam score, s2 = the 2nd score, etc.
The average of the 1st four exams is computed from:
(s1+s2+s3+s4)/4 = 83 -> s1+s2+s3+s4 = 332
The average of 86 for all six exams is computed from:
(s1+s2+s3+s4+s5+s6)/6 = 86 -> s1+s2+s3+s4+s5+s6 = 516
Subtract the 1st equation from the 2nd:
s5+s6 = 184
The average of the last two scores is (s5+s6)/2 = 184/2 = 92
Ans: 92
