Ithink the answer is b. im i right?

What is the standard deviation of the following data set rounded to the nearest tenth? 3, 17, 18, 15, 12, 21, 9

Helena lost her marbles. but then she found them and put them in 44 bags with mm marbles in each bag. she had 33 marbles left over that didn't fit in the bags.

The map shows the location of the airport and a warehouse in a city. though not displayed on the map, there is also a factory 112 miles due north of the warehouse.a truck traveled from the warehouse to the airport and then to the factory. what is the total number of miles the truck traveled?