Adam's average homework score, worth 40% of his grade, is 76%

average-homework

#1

Adam’s average homework score, worth 40% of his grade, is 76%.
His average unit test score, worth another 40%, was 81%. The
final makes up the rest of his total grade. What is the minimum
number of questions he need to answer correctly on the 50-question
final exam to earn a B (80%) in the class?

Answer:

76×0.4+81×0.4=62.8
79.5−62.8=16.7
16.7÷20=0.835
0.835×50=41.75
Round 41.75 up to 42.
42 questions is the minimum number of questions he needs to get right in order to earn an 80 in the class