There are two groups of students in the sixth grade. There are 30 students in group A, and 50 students in group B. If, on a particular day, 20% of the students in group A forget their homework, and 12% of the students in group B forget their homework, then what percentage of the sixth graders forgot their homework? Choose the correct answer.
A) 13 %	B) 14 %	C) 15 %	D) 16 %	E) 17 %

Rationale: total students = 30 + 50 = 80 20 % of 30 = 6 12 & of 50 = 6 total students who forget homework = 6 + 6 = 12 percentage = 1280 ∗ 100 = 15 = 12 / 80 ∗ 100 = 15 ; answer = c = 15 %
Answer: C