Answer:
Total successfully quizzes = 12 + 24 = 36
Average = ( 36 / 50 ) * 100 % = 0.72 * 100 % = 72 %
Step-by-step explanation:
A student has passed 60 percent of the 20 quizzes he has written so far successfully mean:
successfully quizzes = 60 % of 20 quizzes = ( 60 / 100 ) * 20 = 60 * 20 / 100 = 1200 / 100 = 12
The remaining quizzes = 50 - 20 = 30 quizzes
80 percent of the remaining quizzes successfully mean:
The remaining successfully quizzes = 80 % of 30 = ( 80 / 100 ) * 30 = 80 * 30 / 100 = 2400 / 100 = 24
Hope this helps!
He has 30 left to take, and he passes 80%.
(20/50) × 60% + (30/50) × 80% = 24% + 48% = 72%
Answer: 72%