A and B start walking towards each other at 4pm at speed of 2kmph and 3kmph. They were initially 15km apart. At what time do they meet?
Select the correct option:  A) 8 pm  B) 6 pm  C) 7 pm  D) 10 pm  E) 5 pm

Rationale: time of meeting = distance / relative speed = 15 / 3 + 2 = 15 / 5 = 3 hrs after 4 pm = 7 pm answer is c
Answer: C