Question

A field is 80m long and 50m broad.In one corner of the field,a pit which is 8m deep ,10m long and 7.5m broad is dug out.The earth taken out of its is evenly spread over the remaining part of the field.Find the rise in level of the field

Answer 1

Solution:-

Length of field = 80 m
Breadth of field = 50 m 
Length of pit = 10 m
Breadth of pit = 7.5 m
Height of pit = 8 m
Volume of earth taken out = volume of pit
= L*B*H
= 10*7.5*8
= 600 cu m
Area of rectangular field = 80*50
= 4000 sq m
Area of the base of pit = 10*7.5 
= 75 sq m
Area of remaining portion of rectangular field = Area of rectangular field - Area of the base of pit
= 4000 - 75 
= 3925 sq m
Now rise in the level of remaining part of the field = 600/3925
= 0.1528 m or 15.28 cm
So, rise in the remaining part of the field = 15.28 cm
Answer.

Answer 2

Length of field = 80 m

Breadth of field = 50 m  

Length of pit = 10 m

Breadth of pit = 7.5 m

Height of pit = 8 m

Volume of earth taken out = volume of pit

= L*B*H

= 10*7.5*8

= 600 cu m

Area of rectangular field = 80*50

= 4000 sq m

Area of the base of pit = 10*7.5  

= 75 sq m

Area of remaining portion of rectangular field = Area of rectangular field - Area of the base of pit

= 4000 - 75  

= 3925 sq m

Now rise in the level of remaining part of the field = 600/3925

= 0.1528 m or 15.28 cm

So, rise in the remaining part of the field = 15.28 cm