Answer: 128.5km
Explanation:
Since we are given the information that the distance by road from town A to town B is 257 km. To get 50% of the distance, we simply have to multiply the distance given by 50%. This will be:
= 50% × 257km
= 50/100 × 257km
= 0.5 × 257km
= 128.5km
Therefore, 50% of the distance is 128.5km.