question attached

Suppose there is an infectious disease with the potential of spreading in a population and that an effective vaccine is available. In an unvaccinated population each person who contracts the disease remains infectious long enough to give the disease to 8 other individuals (on average). Epidemics can be prevented if a large enough share of the population is vaccinated so that average number of people infected by each patient is reduced below 1. What percentage of the population would need to be vaccinated against the disease to achieve this? (rounded to the nearest percent) 0 3% o 88% o 75% O 95% o 50%