A swimming pool is to be drained by cleaning. If L represents the number of litres of water in the pool `t` seconds after the pool has been plugged off to drain and `L=2000(10-t)^2dot` How fast is the water ruining out at the end of 5 seconds? What is the average rate at which the water flows out during the first 5 seconds?

Explanation

Let L represents the number of litres of water in the pool t seconds after the pool been plugged off to drain , then

`L=200(10−t)^2`

So, Rate at which the water is running out =`−((dL)/dt)`


`((dL)/dt)=−200.2(10−t)(−1)`


=`400(10−t)`


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