Puzzle_10 (Solve this and Win an IPod)

Todays Winner are
1. Sathish Kulal (email:sathish.kulal@gmail.com)
2. Manoranjan Mohanty (MCA - School of Computer and Systems Sciences - JNU)
3. Sourabh Garg - (Hydrabad)
4. sonal vikram

Four friends need to cross a bridge to get back to their home at night. Unfortunately, they only have one flashlight. The bridge is too dangerous to cross without a flashlight, and it’s only strong enough to support two people at any given time.

Each of the them walks at a different speed.
One can cross the bridge in 1 minute,
another in 2 minutes,
the third in 5 minutes,
and the fourth one takes 10 minutes to cross.
How much minimum time they will take to cross the bridge?

Solution:
According to your question let A,B,C,D be the four friend who take 1,2,5,10 minutes to cross the bridge.

NOW
----------
1) A and B go together to other end of bridge with flash light( time take = 2 minutes)
2) B remains there and A returns to the start point with flash light( Time taken = 1 minute)
3) C and D go together to other end of bridge with flash light( time taken = 10 minutes)
4) B returns to the start point with flash light(time taken=2 minutes)
5) Both A and B go to other end of bridge with flash light( time taken=2 minutes)
Total time taken = 2+1+10+2+2=17 minutes.

Solution by : Manoranjan Mohanty

Imprtant:
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