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?

Answer:
C. The balloon starts at a height of 500 ft and rises at a rate of 150 ft.
Step-by-step explanation:
We have been given a graph which represents the height of the balloon over time.
We can see from our graph that y-intercept, which represents the height of the balloon (in thousand feet) at time equals zero, is 0.5. To find the correct y-intercept we will multiply 0.5 by 1000 as height of the balloon is given in thousand feet.
[tex]\text{y-intercept}=(0.5\times 1000)\text{ feet}=500\text{ feet}[/tex]
Therefore, y-intercept represents that the balloon starts at a height of 500 feet.
Now let us find slope of our given line using slope formula.
[tex]\text{Slope}=\frac{y_2-y_1}{x_2-x_1}[/tex]
[tex]y_2-y_1[/tex] is vertical change or rise.
[tex]x_2-x_1[/tex] is horizontal change or run.
Upon substituting given values in above formula we will get,
[tex]\text{Slope}=\frac{3.5-0.5}{20-0}[/tex]
[tex]\text{Slope}=\frac{3}{20}[/tex]
[tex]\text{Slope}=0.15[/tex]
Now let us multiply 0.15 by 1000 as height of balloon is given in thousand feet.
[tex]\text{Slope}=0.15\times 1000=150[/tex]
Therefore, slope of our line is 150 which means that height of balloon is increasing 150 feet per second or balloon is rising at a rate of 150 feet per second.
Upon looking at our given options we can see that option C is the correct choice.