Alice is given the numbers 2,3,5,7, and 9. She must choose a pair of these digits, with the digits being different, to form a two-digit number. How many of the numbers she can construct will be divisible by 3?
Out of a total of: 5 nPr 2 =20 permutations, only these 6 are divisible by 3:
27 , 39 , 57 , 72 , 75 , 93 , Total = 6
