The school hired a guest speaker to come and talk to the students for an evening presentation. The school advertised the presentation to all community members and guaranteed the speaker that attendance would be at least 1,000 people. The school is selling student tickets for $4 and non-student tickets for $6. If the school also guaranteed the total ticket sales would be at least $4,800, what is the minimum income the speaker can make and how many of each type of ticket was sold? Assume the speaker will receive $2.50 for every student ticket sold and $4.50 for every non-student ticket sold.