Question

A $20m$ deep well with diameter $7m$ is dug up and the earth from digging is spread evenly to form a platform $22m\times 14m$. Determine the height of the platform.

Answer 1

$Diameterofthewell=7m$

$Radiusofthewell=7/2m$

$Depthofthewell=20m$

$Volumeofthemuddugfromthewell=\pi r^{2}h$

$=22/7\times 7/2\times 7/2\times 20$

$=770m^3$

$Areaoftherectangularplotwherethemudisspread=22\times 14$

$Lettheheightoftheplotfarmbehmetres.$

$Volumeoftheplotform=Volumeofthemudtakenfromthewell$

$22\times 14\times h=770$

$h=\frac{770}{22\times 14}$

$h=\frac{770}{308}$

$h=2.5m$