a,b,c,d,e sitting in a row what is the probability that a & b sitting adjacent. Pick one
A) 1 / 5	B) 2 / 5	C) 3 / 5	D) 4 / 5	E) 6 / 5

Rationale: total number of arrangement is = 5 ! = 120 favorable event i . e a and b can be arranged in 2 ! and the remaining can be arranged in 4 ! since ab can be in any of the four positions . so 4 ! * 2 ! / 5 ! = 2 / 5 answer : b
Answer: B