Hi, do you have the answer to this question?

The graph below shows the monthly supply and demand for wildlife tours in

Thick Jungle National Park. The wildlife tour industry is perfectly competitive. The

Parks Department recently determined that the first 40 wildlife tours each month do no

harm to the park.

However, beyond 40 tours, each additional tour does damage that

requires an extra $20 of clean-up and maintenance.

I copied it from the online file you have