# Problem of the Month

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## September 2016 Problem

A stock of 650 tons of wood has a 16% moisture content. A month later, as a result of drying, the moisture content reduced to 9 %.                                                                       What is the new weight of the stock?
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## June 2016 Problem

A postman has to distribute 10 identical postcards to 5 mailboxes. By how many ways can he do this ?
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## May 2016 Problem

Ten students are standing in line. How many possibilities do we have to select four out of them, so that no two were neighbors in this line?
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## April 2016 Problem

One year, August has 4 Wednesdays and 4 Sundays.

How many Mondays does this year have?

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## March 2016 Problem

Using numbers 1,2,3,6 and 12 (once each) and operations of subtraction and division, obtain 36.
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## February 2016 Problem

A group of tourists has a lunch. Two different jars of apple juice and of strawberry juice are put on the table.

Each tourist takes a 200-ml glass of fruit cocktail, mixing both juices at random. Jack takes a sixth of the apple juice amount and an eighth of the strawberry juice amount. Every glass contains both juices. How many people are in the group?

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## January 2016 Problem

Find the sum of the digits in the number 1643 x 312534

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## December 2015 Problem

Given     a2 + 1 + a-2 = a + a-1  Without calculating a, find the value of   a129 - a128 + a127 - a126 = ?
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## November 2015 Problem

How can you make a number ABCDE 100001 times bigger without doing any mathematical operations?
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## October 2015 Problem

A rich merchant left a testament: If my wife delivers a boy, after my death she receives 1/4 of my property and my son - 3/4. If this is a girl, my wife receives 3/4 and my daughter - 1/4. A week after the merchant passed away, his wife delivered twins - a boy and a girl. How will you share the heritage between them, respecting the merchant's will?
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## September 2015

128 players start a tennis tournament. How many matches will be played ?Answer through reasoning, without any calculations. -----------------------------------------------------------------------------------------------------------------------

Dear visitors,

thank you for sending me your solutions. Many of them were correct, but not optimal. ------------------------------------------------------- Here is the solution: The goal of the tournament is to eliminate 127 players. For this you need 127 matches. Thus, 127.

With best wishes

Serge Hazanov

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