A man travelled two fifth of his journey by train, one third by bus, one fourth by car and the remaining 3 km on foot. What is the length of his total journey?
180 km
Total journey = x.
(2/5)x + (1/3)x + (1/4)x + 3 = x.
LCM = 60 ⇒ (24 + 20 + 15)x/60 + 3 = x ⇒ 59x/60 + 3 = x ⇒ x = 180.