68. An electric vehicle, after being fully charged, travels from location A to location B and then returns to A, following a specific route. If the car uses the air conditioner on the way to B and turns it off on the way back, the car will run out of power exactly when it returns to A. If the car does not use the air conditioner for the entire journey, it will still have $40 \%$ of its battery left after completing the round trip. If the car uses the air conditioner for the entire journey, it will run out of power 36 kilometers away from A while returning from B. The distance between A and B is $\qquad$ kilometers.
Answer: 63