Four persons can cross a bridge in 3,7,13,17 minutes.Only two can cross at a time.Find the minimum time taken by the four to cross the bridge?
a)10 b)106 c)34 d)20

• Ans: 20 minutes
  First send 17 and 7. After 7 minutes, 7 is at finish and 17 needs 10 more minutes to complete his travel. now send 13. After 10 minutes 17 reaches finish and 13 needs 3 more minutes to complete. now send 3. both 3 and 13 reach destination at the same time after 3 minutes. hence the time taken is 7+10+3=20 minutes..
• 9 years agoHelpfull: Yes(12) No(0)
• 20 is the answere bcoz 1st 13 nd 17 gone. after 13 min 7 person gone afet 4 min 3 min person also gone. so total time is (13+4+3)= 20
  
• 9 years agoHelpfull: Yes(3) No(0)