14.
A classroom is 7 m long, 6.5 m wide and 4 m high. It has one door 3 m x 1.4 m and three windows each measuring 2 m x 1 m. The interior wall is to be colour washed. Find the cost of colour washing at the rate of र 3.50 per m2.
For classroom
l = 1 m b = 6.5 m h = 4 m Area to be colour washed
= 2(l + b) h – [3 x 1.4 + 3 {2 x 1}] = 2(7 + 6.5) 4 – (4.2 + 6)
= 108 – 10.2 = 97.8 m2
Cost of colour washing = 97.8 x 3.50 = र 34.30
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