Henry Ernest Dudeney/Puzzles and Curious Problems/65 - The Pedestrian Passenger/Solution

by : $65$

 * The Pedestrian Passenger

Solution
The puzzlingly obvious answer is: $63$ miles per hour.

seems to believe that the result is somehow counterintuitive or paradoxical.

Proof
Let $\mathbf v_T$ be the velocity of the train relative to the railway.

Let $\mathbf v_P$ be the velocity of the passenger relative to the train.

Then the velocity of the passenger relative to the railway is $\mathbf v_T + \mathbf v_P$.

The result follows when you plug in the numbers.