A woman complete a journey in 20 hours. She travels first half of the journey at the rate of 21 km/hr and second half at the rate of 24 km/hr. Find the total journey in km. Select: A) 334 km . B) 216 km . C) 314 km . D) 448 km . E) 544 km .

Rationale: "0.5 x / 21 + 0.5 x / 24 = 20 - - > x / 21 + x / 24 = 40 - - > x = 448 km . d"
Answer: D