Question

the length breadth and height of a room are 5m ,4m and 3m respectively find the cost of white washing the wall of a room and the ceiling at the rate of rs 7.50 per sq.m

Answer 1

Answer:

l=5m

b=4m

h=3m

lsa+l*b=2*(l+b)*h+l*b

=2*(5+4)*3+5*4

=2*9*3+20

=54+20

=74

cost of white washing 1m=rs 7.5

cost of 74m=7.5*74=rs555

Answer 2

☢︎︎How To Solve :

• We will first find out the total area which is to be white washed. We will calculate this area by first calculating the area of the ceiling which is rectangular in shape. Then we will calculate the area of four walls which are also rectangular in shape. Then we will add all the areas to get the total area. Then we will multiply this by 7.50 to get the total cost of white washing.

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☢︎︎Given :

• Length=5 Meters
• Breadth=4 Meters
• Height=3 Meters

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☢︎︎To Find :

• Cost of White Washing the Wall of a Room

• Ceiling at the rate of rs 7.50 per sq.m

☢︎︎Solution :

• It can be observed that four walls and the ceiling of the room are to be white-washed. The floor of the room is not to be white-washed.

Area to be white-washed = Area of walls + Area of ceiling of room

Calculating The Area~

${ \dashrightarrow{ \sf{= 21h + 2bh + lb}}}$

${ \dashrightarrow{ \sf{= [2 x 5x3+2x4x3+5x4] m²}}}$

${ \dashrightarrow{ \sf{= (30+24+20) m²}}}$

${ \qquad{ \qquad{ \qquad{ \therefore\boxed{{{ \sf\pink{ \frak{= 74 m²}}}}}}}}}$

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Calculating Cost of White Washing~

Cost of white-washing per m² area = Rs 7.50

Cost of white-washing 74 m² area = Rs (74 x 7.50)

${ \qquad{ \qquad{ \qquad{ \therefore\boxed{{{ \sf \pink{ \frak{= Rs 555}}}}}}}}}$

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Therefore

❛❛Cost of White Washing the Wall of a Room is= 74 m² . ❜❜

❛❛ Ceiling at the rate of rs 7.50 per sq.m is Rs 555.❜❜

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