Final answer:
The length of the whole journey is 100 km, found by setting up a proportion where 3/5 of the journey is equivalent to the 60 km remaining and solving for the total length.
Step-by-step explanation:
To find the length of the whole journey, we need to consider that the driver has already traveled 2/5 of the total and has 60 km more to go. Since 2/5 of the journey is already completed, the remaining 3/5 is equivalent to 60 km. To find the full length, we can set up a proportion where 3/5 of the journey is to 60 km as 5/5 (the whole journey) is to the total journey length (T).
The proportion would be 3/5 of T = 60 km. To find T, we would multiply both sides by 5/3 to get T alone on one side of the equation. This gives us T = (60 km) × (5/3).
Calculating this, we get T = 100 km. Hence, the total length of the journey is 100 kilometers.