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Puzzles | (River Crossing, Starting Money, Earrings, Matching Pair)

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  • Difficulty Level : Easy
  • Last Updated : 13 Jan, 2022
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Puzzle 1 : (River Crossing) Seven men and two boys need to cross a river. The one canoe is tiny and can carry either one man or two boys. How many times does the boat have to cross the river for everyone to get to the other side? 
SOLUTION:- The puzzle can be put into the form of a pattern. First, two boys cross. One boy returns. One man cross. Second boys returns. So it takes four trips to carry one man across the river. Since there are seven men, twenty eight crossing are needed to cross all men. One more crossing is required for the boys to get on the other side. So, total of twenty nine crossings are required for everyone to get to the other side. 

Puzzle 2 : (Starting Money) In a game called flip it or dip it, three people flip coins, and the odd person out has to double what others already have. After three games,each person has lost twice and has thirty six pounds. How much did each start with? 
SOLUTION:- Work backwards to solve this problem. Begin with the amount of money the players have 
after the third game, then half two players money and double the third player’s money. This gives you the money after two games. Do this two more times. 

Game       1st player   2nd player   3rd  player 
3rd game       36         36            36

2nd game       18         18            72

1st game       9          63            36

start        58.50       31.50         18.00

Puzzle 3 : (Earrings) Five hundred women live in a remote village in India. Six percent of them wear one earring. Of the other ninety four percent, half are wearing two earrings, half are wearing none. How many earrings are there in total? 

6 % of 500 + 47% of 500*2 
             = (6% of 500)+(94% of 500)
             = (100% of 500)
             = 500
so total 500 earrings in the village.

Puzzle 4 (Matching Pair) : It’s midnight and there is power failure. You have twenty two green socks and thirty five purple socks in your dresser drawer. How many socks do you have to take out to be sure of having a pair that matches. 
SOLUTION : You only need to remove three socks to ensure that you have a matching pair. As only two color socks are present in drawer, so out of three 2 must have same color. 

This article is contributed by Aakash Tiwari. If you like GeeksforGeeks and would like to contribute, you can also write an article using or mail your article to See your article appearing on the GeeksforGeeks main page and help other Geeks. 

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