Question

a room is 5.8 m long , 4.2m wide and 3.2m high .it has one door measuring 1.2m * 2.5 and three windows each measuring 1m * 0.75 m find the cost of whitewashing its walls at thr rate of ₹ 30 per square meter

Answer 1

Step-by-step explanation:

length of room = 5.8m

breadth of room = 4.2m

height of room = 3.2m

lateral surface area (including door and windows= 2×(length+breadth)×height

= 2×(5.8+4.2)×3.2

= 2×10×3.2

= 64sq.m

area of door= 1.2×2.5sq.m

=3sq.m

area of one window = 1×0.75sq.m

= 0.75sq.m

no. of windows = 3

total area of windows= 0.75×3

= 2.25sq.m

lateral surface area excluding door and windows= lateral surface area-(area of door+area of windows)

=64-(3+2.25)

= 64-5.25

= 58.75sq.m

rate of white washing= ₹30/sq.m

total cost = lateral surface area excluding door and windows × rate of white washing

= 58.75×30

= ₹1762.5 (ans)