Three women and three children wish to cross a river in a canoe that will hold only one woman and or two children. they can all row on their own but no one can swim. if a onne way trip in the canoe takes ten minutes, what is the minimum time in which all six people can cross the river

(w,k)
that is amount of women and children lefton original side

ok, first realize you must get children across first because who will row the boat back

first trip: 10min, 2 children across, (3,1)
2nd trip: 20min, 1 kid cross back (3,2)
3rd trip: 30min, 2 kids cross (3,0)
4th trip: 40 min, 1 kid cross baack (3,1)
5th trip: 50 min, 1 woman cross (2,1)
6th trip: 60 min, 1 kid cross back (2,2)
7th trip: 70 min, 1 woman cross (1,2)
8th trip: 80 min, 1 kid cross back (1,1)
9th trip: 90 min, 1 woman cross (0,1)
10th trip: 100min, 1 kid cross back (0,2)
11th trip: 110 min, 2 kids cross back (0,0)

min time is 110 mins or 1hr 50min

The answer is (a) 12-2(-1)(6)2(6)=12