Math Destroyer question

Fellow SDN'ers, I need clarity on this question. Half the population of Green Village is vegetarians, and 35% ride bicycles. If 20% are both vegetarian and ride bicycles, what is the probability that a person chosen at random from Green Village is either a vegetarian or rides a bicycle. A. 95% B. 65% C. 12% D. 83% E. 24% Solution in the back says its B, but if I think of it, why is it simply not: 50/100 + 35/100 = 85/100 or 85% either a vegetarian or rides a bicycle? Why does the 20% even... Math Destroyer question
Source: Student Doctor Network - Category: Universities & Medical Training Authors: Source Type: forums