Calculating Cost with Variables

Hello!

I am trying to calculate a transportation costs based on distance. For example, a driver is paid $10 for every pick up and this pick up charge includes the first five miles of travel. For every mile after the first five miles, the driver is paid an additional $1.50 per mile plus the original pick up fee of $10. If the trip distance is less than the included miles (five), then the total cost should be the pick up charge ($10). Currently my formula is taking a negative integer and producing cost based on that. For example: the formula reads (trip distance - included miles) x (rate per mile) + (pick up charge) or (1-5) x ($1.50) + ($10)=$4 when it should result in $10. I apologize if this doesn't make much sense. I appreciate any help that can be offered!