Digit probability
A young girl gave a young man her phone number during a hurried parting. The young man remembers the 7 digits of her phone number, but in his emotional state he does not remember the order of the digitals. He decided to try to dial the seven digits in some random order. What is the probability that he will get to the right girl on his first try if the digits are:
4, 2, 3, 6, 1, 5, 9