Answer:
Explanation:
Given the rate at which the elevator travels modeled by the expression;
y = 30x where y is the height, in feet, and x is the number of seconds.
If the observatory in the John Hancock Center in Chicago is located in the top floor, 900 feet above the ground, we can calculate the time taken to reach the top floor by substituting y = 900 into the equation and solve for x as shown;
y = 30x
900 = 30x
Rearrange
30x = 900
Divide both sides by 30
30x/30 = 900/30
x = 30
Hence it takes 30seconds for the elevator to reach the top floor