Maria has gotten scores of 75 77 81 and 84 out of a possible

Maria has gotten scores of 75, 77, 81 and 84 (out of a possible 100) on the four midterm examinations for a math class. If each of these midterms counts as 15% of the total grade in the class and the final exam counts as 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 class?

Solution

let the required score in final exam be x

Maria has gotten scores of 75, 77, 81 and 84 on the four midterm examinations

each of these midterms counts as 15% of the total grade in the class and the final exam counts as 40% of the total grade

to get at least 85%

(75/100)*(15/100) +(77/100)*(15/100) +(81/100)*(15/100) +(84/100)*(15/100) +(x/100)*(40/100) =(85/100)

(75 )*(15/100) +(77)*(15/100) +(81)*(15/100) +(84)*(15/100) +(x)*(40/100) =85

47.55+ 0.4x =85

0.4x =85-47.55

0.4x =37.45

x=37.45/0.4

x=93.625

x=94

she must get as a score of 94 (out of 100 possible) on the final examination to get at least 85% as her total grade in the class