Alternate approach — using the inverse time-speed ratio directly:
Running speed is \( 1.4 \) times the walking speed, so for the same distance, running time is \( \frac{1}{1.4} = \frac{5}{7} \) of the walking time.
Walking B to C takes 210 minutes, and running B to A also takes 210 minutes. Since running takes \( \frac{5}{7} \) of the walking time for the same stretch, the walking time for A to B is \( 210 \times \frac{7}{5} = 294 \) minutes.
Similarly, since walking B to C takes 210 minutes, the running time for B to C is \( 210 \times \frac{5}{7} = 150 \) minutes.
So, walking A to B and running B to C together take \( 294 + 150 = \) 444 minutes.