Question

An elevator descends in to a mine shaft at the rate of 7m/min .If its descent starts from 9m above the ground level, how long will it take to reach -205m?
please answer ​

Answer 1

Given:-

• Rate of descending the elevator = 7m/min
• It start descend from 9 m above the ground level.

To Find:-

• How long will it take to reach -205 m

Solution:-

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀According to the Question

It is given that elevator descends in to a mine shaft at the rate of 7m/min .If its descent starts from 9m above the ground level. we have to calculate the time taken to reach -205 m . So let's begin

As the elevator descend 9 m above from the ground level.

So , the distance descended by the elevator = -205 + (+9)

$:\implies$ -196m

Now it is given that the rate of descending the elevator is 7m/min. (we take the rate of descending in negative )

Let the time taken by the elevator be t min .

Therefore,

$:\implies$ rate = Distance/time

Substitute the value we get

$:\implies$ -7 = -196/t

$:\implies$ 7 = 196/t

$:\implies$ 7×t = 196

$:\implies$ t = 196/7

$:\implies$ t = 28 minutes

• Hence, the time taken by the elevator is 28 minutes.

Answer 2

Given :-

An elevator descends in to a mine shaft at the rate of 7m/min .If its descent starts from 9m above the ground level

To Find :-

How long will it take to reach -205m?

Solution :-

Distance covered = -205 + (9)

Distance covered = -205 + 9

Distance covered = -196m

Now

Time = Distance/Speed

Time = -196/-7

Time = 196/7

Time = 28