Question

Find the volume of iron required to make an open box whose external dimensions are
42 cm x 35 cm x 14 cm, the box being 1 cm thick throughout. If 1 cm iron weighs 9 g, find
the weight of the empty box in kilograms.​

Answer 1

volume of iron required=

42*35*14-40*33*13

(13 is taken because box is open)

=20580-17160=3420cm3

weight= 3420*9=30780g

=30.78kg