A rectangular plot is 24 m long and 20 m wide. A cubical pit of edge 4 m is dug at each of the four corners of the field and the soil removed is evenly spread over the remaining part of the plot. By what height does the remaining plot get raised?

Let ABCD be the rectangular plot.

Given,

Length of plot (l) = 24 m

Width of plot (b) = 20 m

So, the area of plot = l × b = 24 × 20 = 480 m².

We know that,

Side of cubical pit = 4 m

Volume of each pit = 4³ = 64 m³.

Volume of 4 pits at the corners = 4 × 64 = 256 m³.

Surface area of each pit = 4(side)²

= 4 × 4²

= 64 m²

So, the area of remaining plot = 480 – 64 = 416 m².

Let height of soil be h meters spread over remaining land.

So, the volume of soil raised = Volume of soil dug

∴ 416 × h = 256

h = $\dfrac{256}{416} = \dfrac{8}{13}$ metre.

Hence, remaining plot gets raised by $\dfrac{8}{13}$ metre.