Question

A plot of land in the form of a rectangle has a dimensions 240×180.A drainlet a 10meter wide is dug all around it (on the outside) & the earth dug out is evenly spread over the plot increasing its surface level by 25cm.Find the depth of the drainlet

Answer 1

Since the rectangular surface level is increased, we can calculated the volume of earth dug and added on the rectangular plot.

Volume of earth dug = 240m x 180m x 0.25m = 10800 m3

 

This volume is also the volume of the drainlet.

= 2(240m x 10m x d m) + 2(180m x 10m x d m) = 10800 m3.

d = depth = 1.29 m

Answer 2

Answer:

1.227m is the correct answer or 1.29-approx