Question

In his mathematics class, John has taken 3 tests, each worth 20% of his total grade. His grades on those tests were 92%,83%,and 85%. He has an 100% average on his homework, worth 10% of his grade. All that remains is a final exam worth 30% of his total grade. To the nearest percent what must he make in the final exam to have a 90% average in the class?

Answer 1

so far he has
.2(92+83+85) + 10
= 62

let his mark on the final be x
62 + .3x = 90
.3x = 28
x = 93.3