Explain how to solve this math problem: Theo has $6000 he wishes to spend on his upcoming business trip to South Africa. He buys 6 business suits at $100 each, 3 suitcases at $50 each, a flight ticket that costs $700 more than 5 times as much as the cost of a business suit. He wishes to save $2000 for this trip, how much does he have to spend on buying gifts for his business partners in South Africa?