An open wooden box `80 cm` long, `65 cm` wide and `45 cm` high, is made of `2.5 cm` thick wood.
Find (i) the capacity of the box, (ii) volume of wood used and (iii) weight of the box, it being given that 100 `cm^(3)` of wood weight `8g`

Explanation

External length of the box = `80 cm`
External breadth of the box `= 65 cm`
External height of the box `= 45 cm`
External volume of the box = `(80 xx 65 xx 45)` cu cm
`= 234000 cm^(3)`
Internal length of the box `= [80 - (2.5 xx 2)] cm = (80 -5)cm`
= 75 cm
Internal breadth of the box `= [65 - (2.5 xx 2)] cm = (65-5) cm`
= 60 cm
Internal height of the box `== (45 - 2.5) cm = 42.5 cm`
(i) Capacity of the box = internal volume of the box
`= (75 xx 60 xx 42.5) cm^(3) = 191250 cm^(3)`
(ii) Volume of wood used
= (external volume) - (internal volume)
`= (234000 - 191250) cm^(3) = 42750 cm^(3)`
Weight of `100 cm^(3)` of wood = 8g
Weight of `42750 cm^(3)` of wood `= ((8)/(100) xx 42750) g = 3420 g`
`= 3 kg 420 g`