And 2 of them each weigh 100lbs. How many trips will they have to make to cross the river?
2007-07-23 05:37:16 · 13 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
1 - both 100 lbers go over and drop 1 off
2 - one 100 comes back
3 - one 200 gets in and goes over
4 - the other 100 brings it back
5 - both 100s get in and drop one off
6 - one 100 comes back
7 - 200 gets in and goes over
8 - the 100 brings it back
9 - both 100s arrive at end
2007-07-23 05:43:46 · answer #1 · answered by miggitymaggz 5 · 2⤊ 1⤋
First, the two 100 lb people cross (1). One of them comes back (2). A 200 lb person crosses (3). The other 100 lb person crosses back (4) and returns with the first 100 lb person (5), who must again cross back (6) so that the second 200 lb person can cross (7). Finally, the 100 lb person on the far side crosses back (8) and returns with the other 100 lb person (9).
The whole problem is that the boat gets stuck on the far side if a 200 lb person uses it without a 100 lb person available to bring it back.
2007-07-23 05:42:52 · answer #2 · answered by DavidK93 7 · 2⤊ 1⤋
First Trip: 100 + 100 - drop one off
Second Trip: 100 returns
Third Trip: 200 goes over
Fourth Trip: 100 comes back
Fifth Trip: 100 + 100 - drop one off
Sixth Trip: 100 returns
Seventh Trip: 200 goes over
Eighth Trip: 100 comes back
Ninth Trip: 100 + 100 - everyone on other side
So 9 trips across the river are required.
2007-07-23 05:45:43 · answer #3 · answered by Daniel A 2 · 1⤊ 0⤋
5.
Trip 1 is with 2 people across the river.
Trip 2 is one of those guys taking the boat back across.
Trip 3 is with 2 people across the river. At this point there are 3 people across.
Trip 4 is one of those guys taking the boat back across. At this point there are 2 people on both sides, and the boat is back where it started at.
Trip 5 is with the last 2 people across the river.
2007-07-23 05:54:01 · answer #4 · answered by Anonymous · 0⤊ 0⤋
3
2007-07-23 05:39:50 · answer #5 · answered by lovinpink809 4 · 0⤊ 2⤋
5
2007-07-23 05:40:33 · answer #6 · answered by Anonymous · 0⤊ 2⤋
Both 100's go 1 100 comes back gets out one 200 man goes the other 100 son comes back both 100's go back again 1 100 goes back the other 200 man goes the 100 lb son goes back and brings back the other 100lbs son
2016-05-21 01:22:34 · answer #7 · answered by julia 3 · 0⤊ 0⤋
3 trips
100+100+200+200 = 600
600/200 = 3
2007-07-23 05:41:13 · answer #8 · answered by Anonymous · 0⤊ 2⤋
1 - both 100 lbs go over and drop 1 off
2 - one 100 comes back
3 - one 200 gets in and goes over
4 - the other 100 brings it back
5 - both 100s get in and drop one off
6 - one 100 comes back
7 - 200 gets in and goes over
8 - the 100 brings it back
9 - both 100s arrive at end
2007-07-23 05:54:25 · answer #9 · answered by Anonymous · 0⤊ 0⤋
2 100 lb people go to the other side - 1 trip
1 comes back --- 2nd trip
1 200lb person goes to other side - 3rd trip
Other 100 lb person comes back - 4th trip
both 100 lb people go to other side - 5th trip
one comes back --- 6th trip
last 200 lb person crosses - 7th trip
other 100 lb person goes back (8th) and returns with 100 lb person (9th)
9 trips
2007-07-23 05:45:25 · answer #10 · answered by nyphdinmd 7 · 1⤊ 0⤋