Question

An aeroplane is 30m long and its model is l5 cm long. If the total outer surface area of the model is 150 cm² , find the cost of painting the outer surface of the aeroplane at Rs. 120 per m², if  5O m² is left out for windows.

Answer 1

15 cm represents = 30m

1 cm represents `30/15` = 2 m

1 cm² represents 2m x 2m = 4 m² 

Surface area of the model = 150cm² 

Actual surface area of aeroplane = 150 x 2 x 2 m² = 600 m²

50 m² is left out for windows 

Area to be painted = 600 - 50 = 50 m²

Cost of painting per m² = Rs. 120 

Cost of painting 550 m² = 120 x 550 = Rs 66000