Question

the length, breath and hight of a room are 5m, 4m ,3 m respectively. find the cost of whitewashing the wall of the room and the ceiling rate of
Rs 7.50 per m²


please post right answer


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Answer 1

Given -

• Length(l) of the room = 5 m
• Breadth(b) of the room = 4m
• Height(h) of the room =3m

To find -

• The cost of white washing the walls of the room and the ceiling at the rate of Rs 7.50 per m²

Solution -

C. S. A of walls of the room =2(lh+bh)

=2(5×3+4×3)

= 2(15+12)

=2×27

= 54m²

Area of the ceiling = l×b

=(5×4)

=20m²

Area of the walls of the room and the ceiling =(C. S. A of wall + Area of the ceiling)

=(54+20)m²

=74m²

Answer 2

Given -

$\sf \: Length \: of \: the \: room \: = 5 \: m \\ \\ </p><p> \sf \: Breadth \: of \: the \: room = 4 \: m \\ \\ </p><p> \sf \: Height \: of \: the \: room =3 \: m$

• Let length be l , Breadth be b, Height be h .

To find -

• The cost of white washing the walls of the room and the ceiling at the rate of Rs. 7.50 per m²

Required Solution :-

$\sf \: C.S.A \: of \: walls \: of \: the \: room \\ </p><p> \sf =2(l \times h)+(b \times h) \\ \\</p><p> \tt \: =2(5×3+4×3) \\ \\</p><p> \sf = 2(15+12) \\ \\</p><p> \sf =2×27</p><p> \sf = 54 {m}^{2}$

$\sf \: Area \: of \: the \: ceiling = l×b</p><p> \\ \sf=(5×4)</p><p> =20 {m}^{2}$

$\therefore \sf Area \: of \: the \: walls \: of \: the \: room \: and \: the \: ceiling =(C. S. A \: of \: wall + Area \: of \: the \: ceiling) \\ </p><p> \sf=(54+20) {m}^{2} \\ </p><p>\implies \sf74 {m}^{2}$