Question

A room is 8.5m long, 3.5m wide and 3.4m high. It has a door 1.4m X 2.5m and a window 2m X 1.55m .find the cost of papering it's walls at 25rupes per metre with a paper 50cm wide?

Answer 1

lateral surface area = 2h(l+b)
                                = 2 x 3.4(8.5 + 3.5)
                                = 81.6 m ^2
area of door = 1.4 x 2.5 = 3.5 m^2
area of window = 2 x 1.55 = 3.1 m^2
total area of window and door = 6.6 m^2
area to be papered = 81.6- 6.6 = 75m^2
area to be papered = area of paper required
75 = 0.5 x length
length = 150 m 
cost = length x  cost
       = 25 x 150
       = rs 3750