Chelsea's last seven test scores are 89, 95, 80, 93, 89, 86, and 92. She has one more test before...

Chelsea's last seven test scores are 89, 95, 80, 93, 89, 86, and 92. She has one more test before the end of the grading period. In order to have an average of at least 90 for the grading period, what is the lowest score Chelsea can get on the final test?