Answer:
4/5
Step-by-step explanation:
If we are given this value as a percent we can simply turn that percentage into a fraction. 80% would be 8/10 but since the question wants the fraction in simplest form we can achieve this by dividing both the numerator and denominator by 2. This would give us 4/5, which if we divide the numerator by the denominator we get 0.80 which is 80%. Therefore, the fraction of those surveyed that had at least one brother or sister is 4/5
