A man walks half of the journey at 4 km/h by cycle does one third of journey at 12 km/h and rides the remainder journey in a horse cart at 9 km/h, thus completing the whole journey in 6 hours and 12 minutes. The length of the journey is	Choose one.
A) 36 km	B) 1332⁄67 km	C) 40 km	D) 28 km	E) None of these
Let the length of the journey = x km.   ∴ Journey rides by horse cart = x(1 - 1⁄2 - 1⁄3)   = 1⁄6x km   Then, total time taken to complete journey = 31⁄5hr   ⇒ t1 + t2 + t3 = 31⁄5   ⇒ x⁄2 × 1⁄4 + x⁄3 × 1⁄12 + x⁄(6 × 9) = 31⁄5   ⇒ x = 31⁄5 × 216⁄37 = 36.2 km ≈ 36 km   36 kmnswer 36 km
<result>A</result>
A man walks half of the journey at 4 km/h by cycle does one third of journey at 12 km/h and rides the remainder journey in a horse cart at 9 km/h, thus completing the whole journey in 6 hours and 12 minutes. The length of the journey is