If each digit in the set of A = {1,2,3,4,5,6,7} is exactly used once, in how many ways can the digits be arranged such that the 2 and 5 are not adjacent?	Choose the correct choice:
A) 7!	B) 5*6!	C) 7! - 6!	D) 7! - 2!	E) 7! / 2!
The answer should be the (total arrangements) - (arrangements when 2 and 5 are adjacent).   The number of ways to arrange 7 units is 7!   If we think of 2 and 5 as one single unit, the number of arrangements is 6!   Note that 2 and 5 can have two arrangements, so we multiply by 2 to get 2*6!   The total number of valid arrangements is 7! - 2*6! = 7*6! - 2*6! = 5*6!   The answer is 5*6!.
<result>B</result>
If each digit in the set of A = {1,2,3,4,5,6,7} is exactly used once, in how many ways can the digits be arranged such that the 2 and 5 are not adjacent?