for N>_4 N=2^x where x is any natural number last person would be 1 and
for 2^k such that 2^k<N<2^(k+1)the last person is 2(N-2^k)+1

well the good answers are 83,82 consider every numbers as number of hours so on a 12 hours clock it will be 11 2 9 4 7 so furthering it will be 6 5 so it will be 83 82
but typical answer 90 sum of two
series

57620 or 57628

the swan will go just less then r/4 distance from centre then start swimming in circles then when the monster and swan are on the same diameter the swan will sim towards the shore and escape

if all pillls are identical then why not eat any two of them
if they look identical then
take one more A pill AND THEN CUT ALLPILLS IN HALF AND EAT HALF OF EVRY PILL AND THE OTHER HALF NEXT DAY YOU DOSAGE WILL BE FINE

$15

chair

0

c

they decide if last person sees odd numbers of yellow hat he will say yellow and red in even numbers of yellow hats .rest is obvious