Question 1112783
The average of the exams is the sum divided by the number of them or 405/5=81
That is 0.6 of the grade so the actual number of the final grade is the product of 0.81 (81%) and 0.6. or 48.6%
The project's contribution is .85*0.1=0.085=8.5%
Going into the final, the score is 57.1%
To make an 80 the score* 0.30 must be 22.9. Therefore, the score is 22.9/0.30, or 76 1/3%
To make a 90, the score*0.30 must be 32.9, so the score needed is 32.9/0.3, or 109 2/3%
The score must be at least 77, to the lowest integer, to get a score of at least 80.  Any higher will be acceptable, and 90 is not possible, even with a perfect score on the project.