That depends upon how many grades made up your 97 average.
your grade would be 94.5
It would only be 94.5 if there were only two grades. What would it be if 5 grades were averaged for the 97%?
To calculate your average after including the test score, you need to consider the weighting of the test in relation to your previous average. If the test is worth a certain percentage, you would need that information in order to determine your new average and grade. Please provide the weight of the test, and I will be able to help you calculate your average and grade accordingly.
