Question 1119691
<br>
When solving a question like this, involving averages of numbers that are all close together, a method that can get you to the answer faster is to compare the given numbers to the desired average.<br>
In this case, with a desired overall average of 80, the current scores are<br><pre>
96  = +16
65  = -15
79  = - 1
87  = + 7
     ----
      + 7</pre>
Overall, the current scores have a "balance" of +7 compared to the desired average.<br>
To obtain the desired average (or better), the minimum score on the 5th test must have a "balance" of -7.<br>
So 80-7 = 73 is the minimum score needed on the 5th test to get an overall average of 80 or higher.