Math problem! please help!?

Maria has gotten scores of 75,77,81 and 84(out of a possible 100) on the four midterm examinations for a math cl. If each of these midterms counts as 15% of the total grade in the cl and the final exam counts at 40% of the total grade, what must she get as a score (out of 100 possible) on the final examination to get at least 85% as her total grade in the cl?