Acuboidal tank can store 6600 litres of water. the external dimensions of the tank are 3.5m, 1.2m and 2.4m. if the walls of the tank are 10cm thick, then what is the thickness of the bottom of the tank

Volume of water
=6600 l=6600×0.001m³=6.6m³

▶Considering only inner volume
Let,
x↪ thickness of bottom of cuboid
Then,
↪h=3.5-x
{to get inner height of cuboid}

↪ b=1.2m-2×10cm=1.2m-0.2m=1m
{to get inner breadth of cuboid we must subtract it from 2×thickness of wall }

↪ l=2.4m-2×10cm=2.4m-0.2m=2.2m
{to get inner length of cuboid we must subtract it from 2×thickness of wall }

❇Since
↪inner volume=volume of water
↪ l×b×h=6.6
↪ 2.2×1×(3.5-x)=6.6
↪ 3.5-x=6.6/2.2
↪ x=3.5-3
↪ x=0.5m➡required thickness

The amount used= 13.04- 1.9 = 11.14