If the speed of trains on Shanghai Nanjing line is increased from 120 km / h to 160 km / h and the time from Shanghai to Nanjing is reduced by 40 minutes, how many km are there on Shanghai Nanjing line?

If the speed of trains on Shanghai Nanjing line is increased from 120 km / h to 160 km / h and the time from Shanghai to Nanjing is reduced by 40 minutes, how many km are there on Shanghai Nanjing line?


Set the distance to x km
X/160 = X/120 - 40/60
X = 320