Question

a closed wooden box of internal dimensions 105cm by 85cm by 30cm is made of 2.5 cm thik wood . calculate each of the following. 1 the intrnal volume of the box. 2 the volume of the wood used to make the box.

Answer 1

$internal \: Dimension \\ l = 105-(2.5 \times 2) = 100cm \\ b = 85 - ( 2.5 \times 2) = 80cm \\ h = 30 - (2.5 \times 2) = 25cm \\ Volume \: of \: cuboid = l \times b \times h \\ V = 100 \times 80 \times 35 \\ V = 8000 \times 30 \: \\ V = 200000 {cm}^{3} \\ \: Inner \: volume = 200000 {cm}^{3} \\ \\ outer \: dimension \\ l = 105cm \\ b = 85cm \\ h = 30cm \\ volume \: of \: cuboid = l \times b \times h \\ v = 105 \times 85 \times 30 \\ = 8925 \times 30 \\ v = 267750 {cm}^{3} \\ \\ Volume \: of \: wood \: = Volume \: of \: outer \: S Dimension \: - inner \: Dimenion \\ V = 200000 - 267750 \\ = 67750{cm}^{3}$