A man complete a journey in 40 hours. He travels first half of the journey at the rate of 20 km/hr and second half at the rate of 30 km/hr. Find the total journey in km.
Choose the correct answer
A) 960 km  B) 224 km  C) 230 km  D) 232 km  E) 234 km

Rationale: "0.5 x / 20 + 0.5 x / 30 = 40 - - > x / 20 + x / 30 = 80 - - > 5 x = 60 x 80 - - > x = ( 60 x 80 ) / 5 = 960 km . answer : a"
Answer: A