A cistern of capacity 8000 litres measures externally 3.3 m by 2.6 m by 1.1 m and its walls are 5 cm thick. The thickness of the bottom is:

Question: A cistern of capacity 8000 litres measures externally 3.3 m by 2.6 m by 1.1 m and its walls are 5 cm thick. The thickness of the bottom is:

[A].

90 cm

[B].

1 dm

[C].

1 m

[D].

1.1 cm

Answer: Option B

Explanation:

Let the thickness of the bottom be x cm.

Then, [(330 – 10) x (260 – 10) x (110 – x)] = 8000 x 1000

320 x 250 x (110 – x) = 8000 x 1000

(110 – x) =	8000 x 1000	= 100
	320 x 250

x = 10 cm = 1 dm.