Question

An open tank with each edge 20 m is to be coated with a metal sheet, on all its faces. If the cost of the sheet is 30 per sq. m, find the
cost of the coating.​

Answer 1

Answer:

$\rm{since \: all \: edges \: are \: equal}$

$\rm{hence \: it \: is \: a \: cube}$

$\rm{edge \: of \: cube = 20m}$

$\rm{total \: surface \: area \: of \: cube = 6 \times {side}^{2} }$

$= 6 \times {20}^{2}$

$= 6 \times 400$

$= 2400$

$\rm{cost \: of \: coating \: 1 {m}^{2} = 30 \: rupees}$

$\rm{cost \: of \: coating \: 2400 {m}^{2} = 2400 \times 30}$

$\rm{ = 72000 \: rupees}$

Answer 2

area of sheet=surface of the tank

the cost of the coating is:-

20×30

=600