soo im really confused on this question and i am not sure what the answer is. the question is, what number fills in the blank 2 + 2 = __

Which of the following is the shape of a cross section of the figure shown below

If x varies directly as y, and x = 7.5 when y = 10, find x when y = 4

Arace is 10 kilometers long. markers will be placed at the beginning and end of the race course and at each 500 meter mark. how many markers are needed to mark the course for the race?