Question

Q16. An open rectangular cistern when measured from outside is 1.35 m long, 1.08 m broad and 90
cm deep. It is made up of iron, which is 2.5 cm thick. Find the capacity of the cistern and the
volume of the iron used.​

Answer 1

$\Large\red{\tt{\mathfrak{Question}}}$

An open rectangular cistern when measured from outside is 1.35 m long, 1.08 m broad and 90 cm deep. It is made up of iron, which is 2.5 cm thick. Find the capacity of the cistern and the volume of the iron used.

$\large\red{\tt{\underline{Answer:-}}}$

Length = 1.35m = 135cm

Breadth = 1.08m = 108cm

Depth = 90cm.

Volume of Cistern:-

=> L × B × H

=> 135 x 108 x 90

=> 1,312,200 cm³

Internal Dimensions:-

¤ Length = 135 - 2.5 - 2.5 = 130 cm

¤ Breadth = 108 - 2.5 - 2.5 = 103 cm

¤ Height = 90 - 2.5 = 87.5 cm.

Internal Volume:-

=> Length × Breadth × Height

=> 130 x 103 x 87.5

=> 1,171,625 cm³

Volume of Iron Used:-

=> 1,312,200 - 1,171,625

=> 140, 575 cm³

Which is the required answer.

Hope this helps.. :)

Thanks.

Answer 2

Answer:

here is your answer mate

Step-by-step explanation:

REF. Image

New length = 1.35−2(0.025)

=1.35−0.05

=1.3m

New breadth = 1.08−2(0.025)

=1.03m

New height = 0.9−2(0.025)

=0.85m

Thickness of iron = 2.5 cm

= 0.025 m

Capacity or volume of cistern = l × b × h

=1.3×1.03×0.85

=1.138m³  

 

Volume of iron used = Volume of cistern (without considering the thickness of iron) - Volume of cistern (after considering the thickness of iron)

=L × B × H − l × b × h

=(1.35×1.08×0.9)−(1.138)

=1.312−1.138

=0.174m³