The circumferences of the fore and hind-wheels of a carriage are 2 2/5 and 3 3/7 meters respectively. A chalk mark is put on the point of contact of each wheel with the ground at any given moment. How far will the carriage have travelled so that their chalk marks may be again on the ground at the same time?	Pick
A) 18 metres	B) 16 metres	C) 38 metres	D) 42 metres	E) 24 metres

Rationale: a little reflection will show that chalk marks will touch the ground together for the first time after the wheels have passed over a distance which is the lcm of 2 2 / 5 metres and 3 3 / 7 metres . lcm of 12 / 5 metres and 24 / 7 metres = 24 metres . answer is e
Answer: E