Question 1182100
<br>
In problems involving averages of numbers that are close together, I find it faster and easier to solve the problem using an "over/under" strategy, rather than the formal definition of an average.<br>
In this problem, using this strategy makes solving the problem almost trivial, because the average on her first four tests is 87.  This is easily seen by looking at the "overs" and "unders" for those tests:
93: +6
87: +0
82: -5
86: -1
total overs and unders on tests 1 to 4: 0<br>
That means the average of her fifth and sixth tests must also be 87.  And since her score on her sixth test was 4 points lower than on her fifth, simple logical reasoning tells us her scores on her fifth and sixth tests were 87+2=89 and 87-2=85.<br>
ANSWERS:
5th test 89
6th test 85<br>