Question

Q50. Twelve students in a class average 70% on a certain test. Eighteen others
average 80%. What is the overall average of the thirty students as a percent?

Answer 1

the attachment shows the question in better form

Answer 2

Twelve students in a class average 70%
Eighteen others average 80%

so sum of scores of 30 students = 12*70 + 18*80 = 2280

Answer 3

divide that by 30 for the overall average