He wants to rent for 20 days and there is a deal if you rent for 14 days so that leaves 20-14 = <<20-14=6>>6 individual days
Each individual day is $50.00 and he will have 6 individual days for a total of 50*6 = $<<50*6=300.00>>300.00
14 days costs $500.00 and 6 days costs $300.00 for a total of 500+300 = $800.00
#### 800