Went by last ferry, first in tour for fewer than thirty (6-4)
I believe the answer is:
twenty-four
'fewer than thirty' is the definition.
I can't judge whether this definition defines the answer.
'went by last ferry first in tour' is the wordplay.
'last' says to take the final letters.
'ferry first' becomes 'f' (1st letter of 'ferry').
'in' is an insertion indicator.
The last letter of 'by' is 'y'.
'went'+'y'+'f'='wentyf'
'wentyf' put within 'tour' is 'TWENTY-FOUR'.
'for' is the link.
Can you help me to learn more?
(Other definitions for twenty-four that I've seen before include "Number of hours in a day" , "Two dozen" .)