Question

. A cistern measuring internally 150cm x 120cm x 110 cm has 129600 cu.cm of water in it. Porous bricks are placed in the water until the cistern is full to the brim, each brick absorbing one-seventeenth of its volume of water. How many bricks can be put in without the water overflowing, each brick being 22.5cm x 7.5 cm x 6.5 cm

Answer 1

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

I hope that's your answer here