16*(150 percent of 2)=16K*1.5=24
When allocating an extent Oracle first looks for a free extent of the same size
we need. If this is not found then we allocate an extent that is the next
multiple of (5 * db_block_size) over the specified extent size if the extent
size is not already a multiple of (5 * db_block_size).
Let's say you have a database with an 8K db_block_size and you create a table
and specify an initial extent value of 96K. When you look in DBA_TABLES you see
the actual initial extent size that you specified however if you look in
DBA_EXTENTS where segment_name = '<TABLE_NAME>' you see that the actual size
of the extent is 120K.
This is because 96K is not a multiple of 40 (which is 5 * db_block_size)
so Oracle rounded up to the next highest multiple of 40 from 96 which is 120.