Answer:
If you get the maximum grade in the last test, your average grade will still be below 0.9 = 90%, which means that it is not possible to average a 90%.
Step-by-step explanation:
Average grade:
The average grade is given by the sum of all averages, divided by the number of tests.
In this question:
99%, 67%, 83%, and 86%.
Next test counts twice, which means that in total, there are 6 tests.
Is it possible to average a 90%?
The maximum grade in a test is 100% = 1. I will calculate the average grade you get a 100% on the last test, which is worth 2. So
[tex]M = \frac{0.99+0.67+0.83+0.86+2*1}{6} = \frac{5.35}{6} = 0.892[/tex]
If you get the maximum grade in the last test, your average grade will still be below 0.9 = 90%, which means that it is not possible to average a 90%.
