A cylindrical well of radius 4m and depth 49 m is dug and the taken out is spread evenly on a ground of length40 m and breadth 28 m. If the volume of the earth taken out increases by 10%, find the increase in the height of the ground.

Explanation

For cylindrical well,
radius r = 4m,
depth h = 49 m
volume `=pi r^(2)h=(22)/(7)xx4xx4xx49=2464 m^(3)`
Increase in the volume of earth taken out `=2464xx(10)/(100)=246.4 m^(3)`
new volume `=2464+246.4`
Now, area of ground `= 40xx28 m^(2)`
`=1120 m^(2)`
`therefore` Increase in the height of ground `=("Volume")/("Area")=(2710.4)/(1120)=2.42 m`