Suppose That Alyson Scores $67$ $87$ $93$ $95$ On Her Algebra Tests, and the Only Test Left to 95

Essay

Suppose that Alyson scores $67$ , $87$ , $93$ , $95$ on her algebra tests, and the only test left to take is the final exam. Her final exam however, accounts for one-half of her overall course average. What range of scores on the final exam would she need in order to achieve an overall course grade of between $80$ and $85$ ?