Question

a room is 9 M long 8 M broad and 6 m high it has to door each of size 3 metre ❌ 1.5 metre and 4 Windows each of size 1.5 m ❌ 1 m find the cost of whitewashing the walls of the room at the rate of rupees 1.75 per square metre

Answer 1

Length of the wall = 9 m
Breadth of the wall = 8 m
Height of the wall = 6 m
Thus, Area of 4 walls = 2h(l + b)
                                   = 2 x 6 (9 + 8)
                                   = 12 x 17
                                   = 204 sq. mtrs.
Length of 1 door = 3 m
Breadth of 1 door = 1.5m
Thus, Area of 2 doors = 2 (3 x 1.5)
                                    = 2 x 4.5
                                    = 9 sq. mtrs
Length of 1 window = 1.5 m
Breadth of 1 window = 1 m
Area of 4 walls = 4( 1.5 x 1 ) m^2
                         = 6 m^2
Area of wall that is to be whitewashed = (204 - 9 - 6) sq. mtrs.
                                                              = 189 m^2
Cost of whitewashing @Rs 1.75/sq. mtr. = Rs (189 x 1.75)  
                                                                 = Rs 330.75