Algebra homework help

Question

Problem: You have a grade of 89% exactly going into your calculus final, and you want to get an A in the class. ​Your final is worth 20% of your overall grade​. 90% is A.What is the lowest possible grade you need on your final to earn the “A?”

Answer 1

The grade of 89 must be worth 80% of the total, which is 0.80 times the the total. To get an average of 90, you need a minimum score x on the final exam such that

0.80(89) + 0.20x = 90

Now solve for x and finish from here.