A closed wooden box 80 cm long, 65 cm wide and 45 cm high, is made of 2.5 cm-thick wood. Find the capacity of the box and its weight if 100cm3 of wood weighs 8 g.
Outer length =80 cm.
Outer width =65 cm.
Outer height =45 cm.
Total volume =80×65×45cm3
=234000cm3
Thickness of wood =2.5 cm.
∴ Inner length =80−2×2.5=75cm.
Inner width =65−2×2.5=60 cm.
Inner height =45−2×2.5=40 cm.
(i)\therefore Inner capacity (volume)
=75×60×40cm33=180000cm3
Volume of wood =234000−180000
=54000cm3
∴ Weight of wood =54000×8100g
=4320g=4.320kg