CareerCup

U missed 3... ppl otr sid cost of travel
1> 1+2 1 comes back => 2 (3)
2> 10+5 2 comes back => 10,5 (12)
3> 1+3 1 comes back => 10,5,3 (4)
4>1+2 =>10,5,3,2,1 (2)

TOTAL : 21

you forgot the 3 but the idea is right. Also step three adds to total 13mins not 15mins

u cant do it in 17 min.

1) 1&2 2sec
2) 1 returns 1sec
3) 5&10 10sec
4) 2 returns 2sec
5) 1&3 3sec
6) 1returns 1sec
7) 1&2 2sec

Total Time = 21 sec

You know, you can do this in 19 minutes...

First let 2 and 1 cross the bridge. Time taken 2 mins.
Then have 1 come back. Time taken 1 mins. Total time 3 mins.
When 1 comes back, Have 10 and 5 cross the bridge. Time taken 10 mins. Total 15 mins
Now when 10 and 5 get on the other side. Let 2 come back. Total time taken 17 mins.
Now 2 and 1 can cross again. Time taken 2 mins. Total time 19 mins.

yeah thats right. 17 mins is the least in which you can do this.