Need to tell the min time to cross the bridge?

Four people need to cross a rickety bridge at night. Unfortunately, they have only one torch and the bridge is too dangerous to cross without one. The bridge is only strong enough to support two people at a time. Not all people take the same time to cross the bridge. Times for each person: 1 min, 2 mins, 7 mins and 10 mins. What is the shortest time needed for all four of them to cross the bridge?

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Permalink Reply by soni kumari on January 30, 2012 at 2:58pm

It will take min 17 min to cross the bridge by all four

Permalink Reply by Heera Singh on January 30, 2012 at 6:36pm

Hi Soni,

I have the same solution but can u please Elaborate the solution.

Thanks,

Heera Singh

Permalink Reply by soni kumari on January 30, 2012 at 8:06pm

For the 1st tym : person who take 1 and 2 min will cross in 2 min, again 1st will get back in other end with torch and ask person who take 7 and 10 mins to cross it will take them 10 mins, now sum is 2+1+10=13min. already 2 min person on the other end Again person with 1 min and 2 min will come back together so all together 17 min

Permalink Reply by charan kumar shake on January 31, 2012 at 2:53pm