In a country with n cities, there is a recurrent one -way flight between every pair of cities. Every flight has a constant price in the range $100, $120, $140, $160, $180.
A $N flight ticket gives unlimited access to flights that cost $N, and tickets can be traded for tickets of lower prices.
For example, with a $160 ticket, Brad could take a $160 ticket, trade his ticket for a $120 ticket, then take a $120 flight.
Alice loves flying and wonders how many successive flights she can take with one ticket.
Determine the minimum value of n needed to guarantee, that she can take 4 such flights.
I must be missing something.
Alice should buy the highest priced ticket available
If n = 2, Alice can take an unlimited number of flights back and forth between the two cities
If the flights must be unique and the end point of one flight must be the starting point of the next, then n=4, allows for a trip of 5 flights.
I do not understand
