Forgot password? New user? Sign up
Existing user? Log in
Problems of the Week
Contribute a problem- Week of December 17
- Week of December 10
- Week of December 3
- Week of November 26
- Week of November 19
- Week of November 12
- Week of November 5
- Week of October 29
- Week of October 22
- Week of October 15
- Week of October 8
- Week of October 1
- Week of September 24
- Week of September 17
- Week of September 10
- Week of September 3
- Week of August 27
- Week of August 20
- Week of August 13
- Week of August 6
- Week of July 30
- Week of July 23
- Week of July 16
- Week of July 9
- Week of July 2
- Week of June 25
- Week of June 18
- Week of June 11
- Week of June 4
- Week of May 28
- Week of May 21
- Week of May 14
- Week of May 7
- Week of April 30
- Week of April 23
- Week of April 16
- Week of April 9
- Week of April 2
- Week of March 26
- Week of March 19
- Week of March 12
- Week of March 5
- Week of February 26
- Week of February 19
- Week of February 12
- Week of February 5
- Week of January 29
- Week of January 22
- Week of January 15
- Week of January 8
- Week of January 1
- Week of December 25
- Week of December 18
- Week of December 11
- Week of December 4
- Week of November 27
- Week of November 20
- Week of November 13
- Week of November 6
- Week of October 30
- Week of October 23
- Week of October 16
- Week of October 9
- Week of October 2
- Week of September 25
- Week of September 18
- Week of September 11
- Week of September 4
- Week of August 28
- Week of August 21
- Week of August 14
- Week of August 7
- Week of July 31
- Week of July 24
- Week of July 17
- Week of July 10
- Week of July 3
- Week of June 26
- Week of June 19
- Week of June 12
- Week of June 5
- Week of May 29
- Week of May 22
- Week of May 15
- Week of May 8
- Week of May 1
- Week of April 24
- Week of April 17
- Week of April 10
- Week of April 3
- Week of March 27
- Week of March 20
- Week of March 13
- Week of March 6
- Week of February 27
- Week of February 20
- Week of February 13
- Week of February 6
When you roll 2 fair dice, is the total more likely to be odd or even?
by
Winston Choo
Are you sure you want to view the solution?
A full can of soda's center of mass is approximately at its center.
What happens to the center of mass of the (can + soda) system as part of the soda is consumed and the can is placed back on the table, until eventually all of the soda is consumed?
Assume that the soda can is in the shape of a uniform cylinder.
by
Anuj Shikarkhane
Are you sure you want to view the solution?
The 2 diagonals of this rectangle divide it into 4 triangles.
If the area of the shaded region is 42, then what is the area of the rectangle?
by
Magdalena Gradek
Are you sure you want to view the solution?
In each square, the blue and red areas are equal.
If R is the radius of the quarter-circle on the left and r is the radius of the circle on the right, what is rR?
by
Jeremy Galvagni
Are you sure you want to view the solution?
I've designed a system which only takes in a prime number as an input and outputs the final digit sum of that number. For example, if I input 997 (a prime), the system will output 7:
997 ⟶ 9+9+7=25 ⟶ 2+5=7.
How many single-digit positive integers cannot be an output of this system?
A prime number is an integer greater than 1 that has no positive integer divisors other than 1 and itself.
View wiki pageA positive number is a number that is greater than zero. (Zero itself is neither positive nor negative.)
by
Pi Han Goh
Are you sure you want to view the solution?