Question

7. A rectangular field measures 30 m by 20 m. A cubical ditch of edge 5 m is dug at each of the
four corners of the field and the earth removed is spread evenly over the remaining field. Find
the increase in the height.
​

Answer 1

Step-by-step explanation:

Volume of well =πr

2

h=

7

22

×3.5×3.5×10=385m

3

Volume of earth dugout = Volume of well =385m

3

Area of remaining field = Area of field - Area of well

=30×20−π(3.5)

2

=600−

7

22

×3.5×3.5=600−38.5=561.5m

2

Now, increase in level of remaining field × Area of remaining field = Volume of earth dugout

⇒Riseinlevel=

Areaofremainingfield

Volumeofearthdaugout

=

561.5

385

=0.686m=68.6cm