All together it equals (of the number of hours he does in a week) 45 because 6 plus 9 is 15 and 15 multipled by 3 is 45 makes sense becuase .. 6 +3 is 9 and 9 +9 is 18 2 weeks equals 14 days 18 subtracted by 14 equals 2 which 45 subtracted by 2 is 43 and that's the esact number of hours he works 43 in a week.
