Question

The ratio of the rate of flow of water in pipes varies inversely as the square of the radius of the pipes. What is the ratio of the rates of flow in two pipes diameters $2$cm and $4$cm?

Answer 1

Radii of two pipes are 1cm and 2cm. Square of the radii of the two pipes are 1cm and 4cm.

$\therefore$ Rates of flow of the two pipes are in the ratio $1:\frac{1}{4}=4:1$