PLEASE HELP ME SOLVE THIS PROBLEM. THANK YOU

A marketer wants to conduct a survey to determine the percentage of customers that interact with advertising on their phones. You need the margin of error of 4% (0.04). How large must your sample be, if you want a 90% level of confidence? The critical value for a 90% level of confidence is 35: Assume you have no preliminary information about the proportion p. The necessary sample size is n: =Lround up to the nearest whole number}. Assume a previous survey gives you an estimate 33:065. Then the necessary sample size is n: =Lround up to the nearest whole number}