Two one-barber shops sit side by side in Dunkirk Square. Each shop can hold a maximum of four people, and any potential customer who finds a shop full will not wait for a haircut. Barber 1 charges $15 per haircut and takes an average of 15 minutes to complete a haircut. Barber 2 charges $11 per haircut and takes an average of 10 minutes to complete a haircut.
On average, 10 potential customers arrive per hour at each barber shop. Of course, a potential customer becomes an actual customer only if he or she finds that the shop is not full. Assuming that interarrival times and haircut times are exponential, which barber will earn more money?