Question

13. A plot of land in the form of a rectangle has a dimension 240 m x 180 m. A drainlet 10 m wide is dug
all around it on the outside) and the earth dug out is evenly spread over the plot increasing its
surface level by 25 cm. Find the depth of the drainlet.
​

Answer 1

✒✒✒✒ ANSWER ✒✒✒✒

Outer length (including drainlet) =(240+20) m =260 m

Outer breadth (including drainlet) =(180+20) m =200 m

∴ area of the drainlet =(260×200)m

2

−(240×180)m

2

=52000m

2

−43200m

2

=8800m

2

Let x be the depth of the drainlet

Then volume of earth dug out = Volume of earth spread on the land

⇒8800×x=180×240×0.25

⇒x=

8800

180×240×0.25

​

=

22

27

​

=1.227 m

PLEASE MARK AS BRAINLIEST ANSWER ❣❣❣❣