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Mathematics

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17 likes 4.2
(Moderate)
100 Balls, 2 Jars in Mathematics
You have 2 jars, 50 red balls, and 50 blue balls. You need to put all the balls into t...
Added about 1 year ago by kash currently with 17 comments
4 likes 4.2
(Moderate)
Pocket Change in Mathematics
I have $36.80 made from an equal number of quarters, nickels, and dimes. How many of ea...
Added about 1 year ago by ig0r currently with 26 comments
5 likes 4.3
(Moderate)
Buying Books in Mathematics
Two friends, Alex and Bob, go to a bookshop, together with their sons Peter and Tim. Al...
Added about 1 year ago by copter currently with 41 comments
2 likes 4.4
(Moderate)
Ten-Digit Number in Mathematics
How many different 10-digit numbers, such as 7,829,034,651, can be written by using all...
Added about 1 year ago by jaX currently with 17 comments
10 likes 4.4
(Moderate)
Running Race in Mathematics
Phil and Sal race each other for 100 yards. Sal wins by 10 yards. They decide to race ...
Added about 1 year ago by copter currently with 27 comments
13 likes 4.5
(Moderate)
Left Hands Only in Mathematics
Assume there are approximately 6,000,000,000 (6 billion) people on Earth. What would yo...
Added about 1 year ago by vette982 currently with 47 comments
8 likes 4.6
(Moderate)
Bugs Eye in Mathematics
You are a bug sitting in one corner of a cubic room. You wish to walk (not fly) to the ...
Added about 1 year ago by ig0r currently with 34 comments
7 likes 4.8
(Moderate)
Prisoners and hats in Mathematics
100 prisoners are standing in a line each 1 seeing the back of the ones in front of him...
Added about 1 year ago by jakab922 currently with 44 comments
23 likes 4.9
(Moderate)
The fake coin in Mathematics
You have 9 coins which all look identical but 1 of them weight less than the others. Yo...
Added about 1 year ago by jakab922 currently with 22 comments
8 likes 5.1
(Moderate)
Don't Hang Yourself in Mathematics
A fool wants to tie a rope around the earth. So he buys a rope of 40,000 KM and ties it...
Added about 1 year ago by copter currently with 30 comments
12 likes 5.2
(Moderate)
Divide 1 to 20 in Mathematics
What is the smallest whole number that can be divided by any number from 1 to 20 (inclu...
Added about 1 year ago by Dusty currently with 25 comments
14 likes 5.4
(Moderate)
Cutting Numbers in Mathematics
When is Seven half of Twelve?
Added about 1 year ago by Tsion currently with 45 comments
4 likes 5.8
(Moderate)
The Four Sevens in Mathematics
(5 + 5) x (5 + 5) = 100 Four 5's written with simple arithmetical signs can be arran...
Added about 1 year ago by dani3l currently with 22 comments
7 likes 5.8
(Moderate)
All Apples in Mathematics
On the market, mrs. Jones and mrs. Smith sell apples. Mrs. Jones sells her apples per t...
Added about 1 year ago by copter currently with 19 comments
16 likes 5.9
(Moderate)
Mutilated Chessboard Problem in Mathematics
Suppose a standard 8x8 chessboard has two diagonally opposite corners removed, leaving ...
Added about 1 year ago by copter currently with 24 comments