The popularity of a new music artist has been growing exponentially each week. The table shows how many song downloads the artist has had so far.
Week Song Downloads
1 - 75
2 - 450
3 - 2700
4 - 16200
Which of the following is a recursive formula that represents the information in the table?

Determine whether the set of whole numbers is closed under addition. explain why the set is or is not closed. give an example.

Check image and write the letter of the answer

Anew obstacle course is home to several new types of challenging obstacles. one such obstacle is traversing a 15-stair staircase. to make it more challenging, the stairs are not uniformly spaced. rather, the vertical space between consecutive stairs for the first 10 stairs is 113 feet and the vertical space for the last 5 stairs is 134 feet. what is the total vertical distance traveled ascending and descending the entire 15-stair staircase?