A balloon is released on top of a building. The graph shows the height of the balloon over time. What does the slope and y-intercept reveal about the situation?

The slope is (change in y)/(change in x). Taking (0, 0.5) and (10, 2) since the x axis is horizontal and the y axis vertical, we get the slope to be (2-0.5)/(10-0)=
1.5/10=3/20=0.15. Since it's based off of 1000 feet, we multiply 0.15 by 1000 to get 150 as the rate of change for every x value. In addition, since we start at 0.5, 1000*0.5=500 and we therefore start at 500 ft. Using the information we have, we therefore have C as our answer