Question 691505
Let x = grade (as a percentage) you get on the final test


Your final is worth 10% of your grade. The remaining stuff is worth 90% of your grade


( 90% of Grade you have Now ) + ( 10% of final ) = Final Overall Grade


( 90% of 77% ) + ( 10% of x ) = Final Overall Grade


( 0.90 * 0.77 ) + ( 0.10 * x ) = Final Overall Grade


Final Overall Grade = ( 0.90 * 0.77 ) + ( 0.10 * x )


Final Overall Grade = 0.693 + 0.10x


You want your final grade to be at least a 70%, so you want this


(Final Overall Grade) > 70%


(Final Overall Grade) > 0.70


(0.693 + 0.10x) > 0.70


0.693 + 0.10x > 0.70


0.10x > 0.70 - 0.693


0.10x > 0.007


x > 0.007/0.10


x > 0.07


So you need at least 7% on the final test to get at least a 70% overall.


Note: you may be thinking that 7% is very very small (too small), but keep in mind that the final is only worth 10% and the bulk of the points are from the remaining 90% (of hw and previous tests/quizzes), so this final doesn't have that much weight compared to finals that are 30%, 40% or 50% of your grade.