A rectangular tank measuring 5m × 4.5m × 2.1 m is dug in the centre of the field measuring 13.5m × 2.5 m. The earth dug out is spread over the remaining portion of the field. How much is the level of the field raised?
Volume = l× b × h
Volume = 5× 4.5× × 2.1=47.25 m3
Area over which it is spread = 13.5 x 25 - 5 x 4.5
= 33.75 - 220 = 11.75 m
Rise in level 
= 4.2 m
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