Question 1090561
<br>If you are working a problem involving averages where the numbers are close together, often a fast way to get to the answer is to compare the individual numbers to the average.  The idea is that if you have an average of x and one number is x-3, then there must be a number x+3 to balance things out.<br>
We can use this method in your example to find the answer very quickly.  One of the current five scores is exactly the desired average; and the two scores of 75 and 65 balance each other out.  The remaining scores are 72 (2 above the desired average) and 69 (1 below the desired average).<br>
So the student's "balance" going into the 6th test is +1; that means she needs to get a score 1 below the desired average in order to get the exact desired average.  So the score she needs to get an average of exactly 70 is 70-1=69.<br>
More realistically, if she needs to get an average of 70 OR MORE to pass, then she needs to get 69 OR HIGHER on the 6th test.