For many years, every day at noon, a mail steamship departs from Le Havre to New York and at the same time a steamship from New York departs for Le Havre of the same company. Each of these steamships is at sea for exactly seven days, and they follow the same route.

How many steamships of its company will a steamship traveling from Le Havre to New York meet on its way?
At the time when a steamship departs from Le Havre, a steamship that left New York 7 days ago arrives in Le Havre.

## Solution

Let's take the departure time of a certain steamship P from Le Havre as the initial time and mark all the steamships it encounters. At the time when steamship P departs from Le Havre, a steamship that left New York seven days ago arrives in Le Havre. By the time steamship P arrives in New York, seven days have passed since the initial moment, and at this moment, a steamship departs from New York - the last one that steamship P meets on its way. Thus, steamship P will meet all the steamships that departed from New York, starting from seven days before the initial time and ending seven days after the initial time - a total of 15 steamships (if we consider that steamships meet when one departs and the other arrives at the same moment).

## Answer

15 steamships.