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:

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
RELATED QUESTIONS
If in a particular course, a student has an average score of less than 90 and not below... (answered by CubeyThePenguin)

for five algebra examinations, maria has an average of 88. what must she score on the... (answered by swincher4391,DrBeeee)

For five algebra examinations, Maria has an average of 92. What must she score on the... (answered by stanbon)

What was the grade a student received on her first examination, if her other grades were (answered by palanisamy)

Rosie has an average of 30 out of 40 for her first six assignments. In order to be top of (answered by fractalier)

lisa has an average of 88 on 8 math tests. what grade must she score on the next test to... (answered by Fombitz)

Paula needs to have an average of 90 to keep her rank in the roll. If she scored 86, 92,... (answered by jorel1380)

Ajay has written a total of seven examinations in a sequence.He scored 90 marks in one... (answered by richwmiller)

On two examinations, you have grades of 89 and 83. there is an optional final... (answered by macston)