To build a road, the length of the repaired road is two fifths of the length of the unfinished road. Who should be regarded as unit 1? What is the proportion of the length of the repaired road to the total length?

To build a road, the length of the repaired road is two fifths of the length of the unfinished road. Who should be regarded as unit 1? What is the proportion of the length of the repaired road to the total length?

If you want to build a road, the length that has been built is two fifths of the length that has not been built
The repaired length accounts for 2 (2 + 5) = 2 / 7 of the total length