Question

The internal dimensions of a rectangular hall are 15m ×12m×4m. There are 4 windows each of dimensions 2m ×1.5m and 2 doors each of dimensions 1.5m ×2.5m. find the cost of whitewashing all the 4 walls of the hall if the cost of whitewashing is rs5 per meter square.
What will be the cost of whitewashing if the ceiling of the hall is also whitewashed

Answer 1

Here,

Ar. of the room or hall=(ar. of the four sides of room+ar.of the ceiling)-ar. of the four windows + ar. of two doors

={2h(l+b)+l×b}-{4(l×b)+2(l×b)}

={2×4m(15m+12m)+15m×12m}-{4(2m×1.5m)+2(1.5m×2.5m)}

={8m×27m+180m²}-{4×3m²+2×3.75m²}

={216m²+180m²}-{12m²+7.5m²}

=396m²-19.5m²

=376.5m²

Given
Cost of white washing 1m²=₹5
₀⁰₀ cost of white washing 376.5m²=₹5×376.5
=₹1882.5

Answer 2

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