Question

The intemel dimensions of rectangular hall are 15 mx 12 mx 4 m. There are 4 windows each of dimension 2 mx 1.5 m and 2 doors each of dimension 1.5 mx 2.5 m. Find the as of white washing all four walls of the hall, if the cost of white washing is 5 per m2 .What will be the cost of white washing if the ceiling of the hall is also white washed?​

Answer 1

Step-by-step explanation:

given l = 15 mt , b = 12 mt , h = 4 mt

then area of four walls = 2 ( l+b )h

= 2 ×(15+12)×4

= 2×27×4 =216 sq mt.

area of four windows = 4× ( l×b)

= 4× ( 2×1.5)

= 4×3 = 12 sq mt

area of two doors = 2 × (l×b)

=2× (1.5×2.5)

= 2×3.75 = 7.5 sq mt

area of ceiling = (l×b)

= ( 15×12) = 180 sq mt

area for white washing = 216 +180 -(12+7.5)

= 396-19.5 = 376.5 sq mt

cost of white washing = 376.5 × 5 = 1882.5 rupees

Answer 2

Given,

Internal dimension of rectangular hall = 15m × 12 m × 4 m

Now,

Area of 4-walls = 2(l + b) × h

= 2(15 + 12) × 4

= 2 × 27 × 4 m²

= 216 m²

Area of 4 windows of size = (2 × 1.5) × 4 = 12 m²

Area of 2 door of size = 2 × (1.5 × 2.5) = 7.5 m²

So, area of remaining hall = 216 – (12 + 7.5) = 216 – 19.5 m² = 196.5 m²

And,

Cost of white washing the walls all four halls of the house is at the rate of ₹5 per m²

= 196.5 × 5 = ₹982.50

Area of ceiling = l × b = 15 × 12 = 180 m²

Cost of white washing = 180 × 5 = ₹900

Therefore, the total cost for white washing = ₹982.50 + 900.00

= ₹1882.50

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