The highest quintile of an income distribution refers to the top 20% of incomes. To determine the total amount of income comprising the highest quintile in this case, we need to sort the incomes in descending order and then sum up the incomes of the top two individuals.
Sorting the given incomes in descending order, we have:
$125,000, $105,000, $98,000, $89,000, $72,000, $63,000, $55,000, $46,000, $38,000, $23,000
The top two incomes in this distribution are $125,000 and $105,000. Adding these two amounts together gives us a total income of $230,000 for the highest quintile.