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In front of you, there are 9 coins. They all look absolutely identical, but one of the coins is fake. However, you know that the fake coin is lighter than the rest, and in front of you is a balance scale. What is the least number of weightings you can use to find the counterfeit coin?

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There are three bags.The first bag has two blue rocks. The second bag has two red rocks. The third bag has a blue and a red rock. All bags are labeled but all labels are wrong.You are allowed to open one bag, pick one rock at random, see its color and put it back into the bag, without seeing the color of the other rock.

How many such operations are necessary to correctly label the bags ?

How many such operations are necessary to correctly label the bags ?

Difficulty Popularity

Rohit is on his way to visit your Grandma, who lives at the end of the state.It's her birthday, and he want to give her the cakes that he has made.Between his place and her grandma house, he need to cross 7 toll bridges.

Before you can cross the toll bridge, you need to give them half of the cakes you are carrying, but as they are kind trolls, they each give you back a single cake.

How many cakes do rohit have to carry with him so he can reach his grandma home with exactly 2 cakes?

Before you can cross the toll bridge, you need to give them half of the cakes you are carrying, but as they are kind trolls, they each give you back a single cake.

How many cakes do rohit have to carry with him so he can reach his grandma home with exactly 2 cakes?

Difficulty Popularity

Tanu lives on the 13th floor takes the elevator down to the ground floor every morning and goes to her office.

In the evening, when she comes back on a rainy day , or if there are other people around in the elevator, she goes to her 13th floor directly. Otherwise, she goes to the 1oth floor and walks up three flights of stairs to his apartment.

Whats the reason for her unusual behavior ?

In the evening, when she comes back on a rainy day , or if there are other people around in the elevator, she goes to her 13th floor directly. Otherwise, she goes to the 1oth floor and walks up three flights of stairs to his apartment.

Whats the reason for her unusual behavior ?

Difficulty Popularity

You have two strings whose only known property is that when you light one end of either string it takes exactly one hour to burn. The rate at which the strings will burn is completely random and each string is different.

How do you measure 45 minutes?

How do you measure 45 minutes?

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