Help with a and b

A) A local news team visited 2 mcdonalds in the city of chicago and ordered Large Fries at each location. One order included 86 fries while the other came with 100. Assuming that the population is normally distributed, find a 90% confidence Interval for the population mean number of fries in an order of Large fries from mc Donalds in chicago. B) 225 Chicago residents were selected at random and asked if they plan to vote in the upcoming federal election. 81 of them said they would. Find a 99%% confidence interval for the population portion of Chicago residents who will vote in the upcoming Federal election