Interview Question for Data Analyst at Detica:

First work out the probability that none have the same number:
In this case imagine each person picks their random number in turn.
From person one through five, probabilities of picking unique numbers:

For person one: 10/10 (since no other numbers have been picked yet)
For person two: 9/10 (since one number has been picked by person one)
Person three: 8/10 (Assume that persons one and two have picked unique numbers, since we are looking for the prob. that ALL have picked unique numbers)
Person four: 7/10
Person 5: 6/10

Multiply together: get 30,240/100,000 = 30.24%
Subtract from 100% to get 59.76% (required answer)