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 :

Solution (By Examveda Team)

Let the thickness of the bottom be x cm
Then,
$$\left[ {\left( {330 - 10} \right) \times \left( {260 - 10} \right) \times \left( {110 - x} \right)} \right]$$       $$ = 8000 \times 1000$$
$$ \Rightarrow 320 \times 250 \times \left( {110 - x} \right) = $$       $$8000 \times 1000$$
$$\eqalign{ & \Rightarrow \left( {110 - x} \right) = \frac{{8000 \times 1000}}{{320 \times 250}} \cr & \Rightarrow \left( {110 - x} \right) = 100 \cr & \Rightarrow x = 10\,cm \cr & \Rightarrow x = 1\,dm \cr} $$