four people want to pass a bridge the bridge is in the dark and everyone who wants to pass it has to take a torch with him they have only one torch in all , and the bridge can only sustain two people on it if they pass the bridge alone it takes 1,2,5,10 minutes of them the question is how long it will take them to pass the bridge at least? for instance:1 and 5 pass then 1 take the torch back 2 and 10 pass then 2 take the torch back 1 and 2 pass it will take 5+1+10+2+2=20 minutes ,but it is not the least

2+1 + 5+1 +10 = 19 minutes

thanks for your answer , soso but 19 minutes is not the least try it again[em44]

i'll post the answer to this question tomorrow

10 ＋1 ＋2 ＝13

Well, maybe the question allows one exception - the bridge is not long and people can pass it with the torch at the other end of the bridge. In that case 10 + 2 = 12 minutes will be okay.

now let's come to the answer to this question 1 and 2 go then 1 back 5 and 10 go then 2 back 1 and 2 go 2+1+10+2+2=17 minutes that's the least :lol have you considered that?[em07]

well, that's terrific - just out of my consideration. never expected the two may need to come back.

我没有看明白。翻译软件用