Pls help with 22 and 23

Maria walks a round trip of 0.75 mile to school every day.how many miles will she walk in 4.5 days

This assignment is past the original due date o this data is from a sample. calculate the mean, standard deviation, and variance 16.7 11.1 46.7 14.8 13.3 16.6 18.5 47.3 42,8 show the following answers to 2 decimal places. sample mean- sample standard deviation ( use the standard deviation above for your calculation.) sample variance ooops- now you discover that the data was actually from a population! so now you must give the population standard deviation.

The sales tax for an item was $8.40 and it cost $420 before tax. find the sales tax rate. write your answer as a percentage.