Waec Model Questions Vol1 2018 Civic Education Question 41

In a community of 20,000 people the following survey data were obtained: - 12% have tried alcohol, 8% have tried marijuana, and 5% have tried both. - Among alcohol users, 30% also use other illegal drugs (excluding marijuana). - Among marijuana users, 20% also use other illegal drugs (excluding alcohol). - Among those who use both alcohol and marijuana, 40% also use other illegal drugs. A drug‑education programme is introduced that reduces the proportion of people using other illegal drugs by 40% and reduces the prevalence of alcohol and marijuana use each by 20% (the reduction applies uniformly to all users of the respective substance). Assuming the percentages for overlaps remain the same after the reductions, what is the total number of people who will be using any illegal drug (alcohol, marijuana or other) after the programme?