Question

A building has two elevators that both go above and below ground. At a certain time of day the travel time it takes elevator A to reach height h in meters is 0.8h+16. The travel time it takes elevator B to reach height h in meters is -0.8h+12 seconds. How long would it take each elevator to reach ground level at this time?

Answer 1

It will take 16 seconds for elevator A to reach ground level.

It will take 12 seconds for elevator B to reach ground level.

Explanation:

We have been given that a building has two elevators that both go above and below ground.

At a certain time of day the travel time it takes elevator A to reach height h in meters is 0.8h+16. We can see that at this time lift is going above the ground as it has a positive slope.

The travel time it takes elevator B to reach height h in meters is -0.8h+12 seconds. We can see that at this time lift B is going below the ground as it has a negative slope.

To find the time it would take for each elevator to reach ground level at the given time we will substitute h=0 in both of our given expressions as at height equals zero both elevators will be at ground level.

`\text{Time it will take elevator A to reach ground level}=0.8*0+16`

`\text{Time it will take elevator A to reach ground level}=0+16`

`\text{Time it will take elevator A to reach ground level}=16`

Therefore, it will take 16 seconds for elevator A to reach ground level.

`\text{Time it will take elevator B to reach ground level}=-0.8*0+12`

`\text{Time it will take elevator B to reach ground level}=-0+12`

`\text{Time it will take elevator B to reach ground level}=12`

Therefore, it will take 12 seconds for elevator B to reach ground level.