Counterexample:
The list o 25 working tenures can possibly be like this
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 12, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25
The 25 data points are listed in ascending order, where the data point for Donald (3rd position in the 3rd quintile) is indicated in bold. Since the person #12 and Donald (#13) have the same tenure, there are only 11 employees with shorter tenures than Donald while there are 12 employees with longer tenures than Donald.
Since the problem did not say that the ‘set’ contains 25 data points – it only said that 25 tenures are ‘listed’ in ascending order --, I thought the 4th answer choice would be the correct answer.
Any thoughts? Thanks!