Statement1: In one of the 7 days, 20 ships departed.
No matter what day 20 ships departed, we have another 6 days that the company sent out at least 1 ship every day.
Let's count: 20+1+1+1+1+1+1=26.
For a certain seven days, at least 26 ships departed. Sufficient
Statement2: For a certain seven days, the numbers of ships departed are different each day.
Let's count the minimum possible numbers of ships departed
...
No matter what day 20 ships departed, we have another 6 days that the company sent out at least 1 ship every day.
Let's count: 20+1+1+1+1+1+1=26.
For a certain seven days, at least 26 ships departed. Sufficient
Statement2: For a certain seven days, the numbers of ships departed are different each day.
Let's count the minimum possible numbers of ships departed
...
