Answer:
Thomas needs to pay additional US$ 27 for the 15 extra miles not included in the mileage.
Step-by-step explanation:
1. Let's review the information given to us for solving the question:
Mileage included with the rental = 54 miles
Additional mile over 54 miles = US$ 1 4/5
Distance finally driven by Thomas = 69 miles
2. Let's calculate how much additional money Thomas needs to pay.
Extra miles driven by Thomas = Distance finally driven - Mileage included
Extra miles driven by Thomas = 69 - 54
Extra miles driven by Thomas = 15
Cost of the additional miles = 15 * 1 4/5
Cost of the additional miles = 15 * 1.80 ⇒ 4/5 = 0.80
Cost of the additional miles = 27
Thomas needs to pay additional US$ 27 for the 15 extra miles not included in the mileage.