Question

a cister internally measured 150 × 120 × 110 cm has 129600 cm ^3 of water in it.Porous brick are placed in water until cister is filled . Each brick absorbs 1 / 17 th of its own volume of water . Find no. of bricks without water overflowing , each brick being 22.5 cm × 7.5 cm × 6.5cm.

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Answer 1

Answer:

1792

Step-by-step explanation:

Dimensions of cistern:

Length = 150 cm

Breadth = 120 cm.

Height = 110 cm.

Volume of cistern = lbh

                              = 150 * 120 * 110

                              = 198000 cm³.

Let n bricks can be put in the cistern without over flowing water.

Then,volume of n bricks = n * (22.5 * 7.5 * 6.5)

                                        = 1096.875n cm³.

Given that Each brick absorbs (1/17)th of its own volume of water.

So, Volume of water absorbed by n bricks.

= (1/17) * 1096.875n

= 64.52 cm³

∴ 1096.875 * n + 129600 - 64.52 * n = 1980000

⇒ 1032.375 * n = 1850400

⇒ n = 1850400/1032.375

⇒ n = 1792.37.

Therefore, 1792 bricks were placed in the cistern.

Hope it helps!

Answer 2

Step-by-step explanation:

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