A cistern, internally measuring 150cm x 120cm x 110cm,has 129600 cubic cm of water in it.Porous bric

Asked by  | 9th Mar, 2008, 12:14: PM

Expert Answer:

Answer to your question is “A cistern, internally measuring 150cm x 120cm x 110cm,has 129600 cubic cm of water in it. Porous bricks are placed in the water until the cistern is full to the brim.Each brick absorbs one-seventeenth of its own volume of water. How many bricks can be put in without overflowing the water, each brick measuring 22.5cm x 7.5cm x 6.5cm"?
Volume of cistern = 150cm x 120cm x 110cm = 1980000 cm3
 Volume of water = 129600 cm3
Volume of brick = 22.5cm x 7.5cm x 6.5cm =1096.875 cm3
Volume of water absorbed by the brick =1/17(Volume of brick) =64.52 cm3
 Now let x bricks can be put in the cistern  = 1096.875x
So volume of water displayed by   x bricks = 64.52 x
Change in the volume of water after dropping the bricks = 129600 - 1096.875x -64.52 x
Water will not overflow if above volume = 1980000
129600 +1096.875x -64.52 x=1980000
Solving we get
1032.355x= 1787400
X = 1731.381162
So 1731 bricks are required

Answered by  | 9th Mar, 2008, 02:09: PM

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