Question

A model of an aeroplane is made to a scale of 1:400. Then what is the length, in cm, of the model; if the length of the aeroplane is 40 m and what is the length, in m, of the aeroplane, if the length of its model is 16 cm?

• A. $12cm$ and $66m$
• B. $10cm$ and $64m$
• C. $12cm$ and $64m$
• D. $10cm$ and $66m$

Answer 1

The correct option is B

$10cm$ and $64m$

Model of an aeroplane to the actual= 1:400

$\therefore$ Scale factor= $\frac{400}{1}$

(i) Length of aeroplane = 40 m

Then length of model = $\frac{40\times 1}{400}=\frac{1}{10}m$

$=\frac{1}{10}\times 100=10cm$

(ii) Length of model= 16 cm

$\therefore$ Length of aeroplane= $\frac{16\times 400}{1}=6400$

$=\frac{6400}{100}=64m$