I need help with this one please.

You are the operations manager for an airline and you are considering a higher fare level for passengers in aisle seats. How many randomly selected air passengers must you survey? Assume that you want to be 99% confident that the sample percentage is within 15 percentage points of the true population percentage. Complete parts (a) and (b) below a. Assume that nothing is known about the percentage of passengers who prefer aisle seats! n= (Round up to the nearest integer.) b. Assume that a prior survey suggests that about 37% of air passengers prefer an aisle seat n (Round up to the nearest integer.)