It is desired to carry out a study in order to estimate the average monthly expenditure on medicines, and the proportion of people who do not have health insurance, for the city "Rest". It has been established that the average expenditure must be estimated with an estimation error no greater than 2.5 nuevos soles, and that the proportion of people without health insurance must be estimated with an error no greater than 0.03. In a similar study carried out 5 years ago, using a sample of size 30, it was found that: the average expenditure on medicine was 80 soles, with a standard deviation of 25 soles; that 30% of people worked independently and that 40% of people did not have health insurance. Determine the minimum sample size required to carry out the study with 95% confidence, if it is known that the city "The rest" has a working population of 2300 people.