There is an elevator in a building that is 450 feet tall with 30 stories. Starting from the 20th floor, the elevator descends steadily toward the bottom floor, passing the 15th floor half a minute after its descent started. The graph below summarizes this information. Based on the graph, determine how fast the elevator travels and the time it would take to go from the 20th floor to the bottom of the building.

Question

Mathematics

Logan Valenzuela

4 March, 10:10

There is an elevator in a building that is 450 feet tall with 30 stories. Starting from the 20th floor, the elevator descends steadily toward the bottom floor, passing the 15th floor half a minute after its descent started. The graph below summarizes this information. Based on the graph, determine how fast the elevator travels and the time it would take to go from the 20th floor to the bottom of the building.

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Nathalia · Answer 1

A floor is 450/30=15ft

It descends at a rate of - 5floors/.5min which is - 5*15/.5=-150ft/min.

h=20*15-150t

h=300-150t and we want to know how long it takes until h=0 so

300=150t

t=2 min

So it will take 2 minutes to go from the 20th floor to the bottom.