A rental company charges a fixed amount of money per day and an additional fee charged for every mile that customers travel using its trucks. A farmer is charged $150 for the two days he used the truck for 50 miles in which he hired the truck to transport hay from a store to his farm. A week later, the customer is charged $76 for using truck 30 miles to move a cow from his farm to the market. Determine the fixed amount that the rental company charges per day and the additional charges per mile for its trucks.