Question

Of the students that took a survey about after-school-activities, 30% said that they watch television, 1/2 said they go to sports practice, and the remaining said they do homework. What fraction represents the students that do homework?

Answer 1

30% + 50% + ? = 100% so ? = 20% for homework.
20% is 20/100 = 1/5 is the fraction that does homework.