Question

9. A room is 40 m long, 30 m broad and
10 m high. Find the cost of whitewashing
its four wall and ceiling at 20 per sq m.​

Answer 1

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Area to be white washed = 2 (by+hl) +lb

= 2(30×10+10×40) +40×30

= 2(300+400) +1200

= 2(700) +1200

=1400+1200

= ${2600m}^{2}$

Cost of white wash of =${1m}^{2}$

= Rs. 20

Cost if white wash of =${2600m}^{2}$

= $\frac{2600}{20}$

=Rs.130

Answer 2

Step-by-step explanation:

Area to be white washed = 2 (by+hl) +lb

= 2(30×10+10×40) +40×30

= 2(300+400) +1200

= 2(700) +1200

=1400+1200

=${2600m}^{2}$

Cost of white wash of =${1m}^{2}$

= Rs. 20

Cost if white wash of =${2600m}^{2}$

=$\frac{2600}{20}$

=Rs.130