A rectangular plot is of length 13.5 metre and breadth 2.5 metre. A rectangular tank (5 x 4.5 x 2.1 metre) is dug in it. The soil taken out from it is spread uniformly in the remaining part of the plot. Find increase in the height of the surface of plot.

Rectangular Plot & Tank Math Solution: Tank Volume $= 5$$\times$ 4.5 $\times$ 2.1 = 47.25\ m^3. Remaining Area $= (13.5$$\times$ 2.5) - (5 $\times$ 4.5) = 33.75 - 22.5 = 11.25\ m^2. Height Increase $=$$\frac{\text{Volume}}{\text{Remaining Area}}$ = $\frac{47.25}{11.25}$ = $\mathbf{4.2\ \text{metres}}$.