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4
6
Charlie and the Chocolate Factory
Charlie once visited chocolate factory to buy some chocolates.Chocolate cost Rs. 3 each and he had only Rs. 45.He was disappointed. He wanted more.
But when he reached the factory he was amazed. There
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Easy
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9
19
Multiples of 8 plus 1
Squaring the first several odd numbers reveals the following pattern:
3 squared = 8 + 1
5 squared = 24 + 1
7 squared = 48 + 1
8, 24, and 48 are all multiples of 8. Does this pattern hold for all squa
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Doable
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7
7
1978
The year 1978 is such that the sum of the first two digits and the latter two digits is equal to the middle two digits, i.e. 19 + 78 = 97. What is the next year (after 1978) for which this is true?
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Doable
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17
14
No if() Only abs()
Given two variable a and b, construct a function f(a,b) which return the maximum one in {a,b}.
You can only use +- · / and abs() (to take the absolute value). NO if() is allowed in your construction.
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Submitted by MoralMachine
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Doable
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25
10
All the King's Wine
So there's this king. Someone breaks into his wine cellar where he stores 1000 bottles of wine. This person proceeds to poison one of the 1000 bottles, but gets away too quickly for the king's guard
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Hard
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19
4
The Sinking Island
You and 3 friends are on an island that is sinking. There is one bridge from the island to the mainland that supports at most 2 people at once. However, it's dark outside so anyone crossing the bridge
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Doable
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10
2
Odd Pills
Your pharmacist gives you 5 jars filled with pills. The pills contained in each jar have an identical appearance and size (i.e. if you mixed all of the pills you wouldn't be able to tell them apart).
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Doable
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4
11
Gold or silver?
What weighs more, a pound of silver or a pound of gold?
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Easy
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5
5
Partitioning a set
In how many ways can a set of r objects be partitioned into subsets of k objects such that:
all subsets are mutually exclusive
each of k-object subset appears in exactly one of the partitions [Partit
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Hard
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10
12
Bit Pair Swap
In one line of C or Java, how would you swap every pair of bits in a byte? That is, swap bits 0 and 1, 2 and 3, 4 and 5, 6 and 7.
Example: 0110 1010 becomes 1001 0101.
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Doable
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11
6
Cocktail Party
You are observing a cocktail party that has seven guests. You notice that each guest shakes hands with one another once they meet, but never again. How many handshakes occurred during the cocktail part
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Easy
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5
5
Non-Adaptive 12 Identical Balls
Okay - so I posted this puzzle to reddit a few weeks ago and one guy had the following comment:
Same problem, but your solution must be non-adaptive. IOW, specify the weighings that you will make up f
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Hard
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10
6
Swap Variables in Place without XOR
Suppose you have two variables, a and b. How can you swap their values without using a temporary variable and also without using the bitwise operator XOR?
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Doable
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12
18
12 Identical Balls
You have 12 identical balls. One of them is slightly different in weight than the rest. You have three weighs of a balance scale to determine which ball is different and whether it is heavier or li
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Doable
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6
4
Sum of Two Prime Numbers
If p, q > 2 are consecutive in set of primes. Since p,q can only be odd number, (p+q) is an even number.
Can (p+q)/2 be prime?
from http://republicofmath.com/
Submitted by MoralMachine
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Doable
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