John surveyed a group of people about their knowledge of rats. To the nearest tenth of a percent, he found that 86.8% of the people surveyed thought rats carried diseases. Of the people who thought rats carried diseases, 45.7% said that rats frequently carried rabies. Since rats do not frequently carry rabies, these 21 people were mistaken. How many total people did John survey?
21 people represent 45.7 % of the total people surveyed....
.457 x == 21 solve for 'x'