Question

An aeroplane is 30 m long and its model is 15 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 the rate of Rs.120 per sq. m. Given that 50 sq. m of the surface of the aeroplane is left for windows.

Answer 1

15cm represents = 30 m

1cm represents`(30)/(15)=2 "m"`

1 cm² represents   2m × 2m = 4 m²
Surface area of the model = 150 cm²

Actual surface area of aeroplane =150 × 2 × 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 × 550 = Rs. 66000