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Guest Message by DevFuse
 

Barcallica

Member Since 27 Apr 2012
Offline Last Active Feb 27 2015 09:04 AM
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Topics I've Started

Average number of spots

01 September 2014 - 09:27 AM

A die is rolled until a 6 occurs. What is the average total number of spots seen on the die before 6 occurs. For example 1,5,2,6 then the number is 1+5+2+6=14.


Sum of circumferences

28 August 2014 - 02:36 AM

What is the sum of circumferences of the infinite stack of circles in the pitcure?

What is the sum of areas?

 

Attached File  Untitled.jpg   16.35KB   7 downloads


Balls

25 August 2014 - 07:13 AM

There are 10 blue balls on a circle, all have different mass. I put green balls between every 2 neighboring blue balls, which weighs the difference of those 2 blue balls. Prove that I can put those green balls in two groups that weigh same. 


How many are there?

22 August 2014 - 02:52 AM

How many natural numbers are there, whose digits increase left to right? (this is from a book, so some of you might already know this one)


8th Graders olimpyad problem

13 August 2014 - 08:31 AM

This is a problem presented in local math olimpyad,

 

N(12,34)=12131415.....31323334

 

Find a, b, c, d where ab+cd=99 and N(ab,cd) is dividable by abcd (4 digit number).