Henry Ernest Dudeney/Puzzles and Curious Problems/226 - The Circulating Motor-Car/Solution

Puzzles and Curious Problems by Henry Ernest Dudeney: $226$

A car was running on a circular track such that the outside wheels were going twice as fast as the inside ones.

What was the length of the circumference described by the outer wheels?

The wheels were $5$ feet apart at the axle-tree.

Approximately $62.832$ feet.

As the outer wheels are going twice as fast as the inner wheels, they are travelling along a circle of twice the circumference.

The circumference is propportional to the radius.

It follows that the radius of the outer circle is twice $5$ feet, that is, $10$ feet.

From Perimeter of Circle that is $2 \times \pi \times 10$ which is approximately $62.832$ feet.

$\blacksquare$