In order to find the grade average, you have to multiply each item for its percentage and add the results. Since the statement indicates that the final is 20% of the grade and she forgot to do it, that means that she got 0 for that 20%. Also, we can say that the average she has of 85 represents 80% of her grade and you have to multiply the average for the percentage:
85*0.8= 68
According to this, the answer is that her final average now is 68.
