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Last month's solutions

Solution: You can either try counting the lines in the diagram, or, use this handy shortcut formula, n*(n1)/2 Using the formula n*(n1)/2 where n = the number of points on the circle:
This formula can also be used for counting the number of individual handshakes in a group, one time per pair of individuals and is created as follows: If you have n points on a circle, each point would have (n1) lines or connections with each of the other points on the circle except itself. The total lines for all points (n) would be n*(n1) and since each pair of points also has a duplicate reverse connection (i.e.., x to y and y to x), then n*(n1) must be divided by 2 to provide the final summing formula of n*(n1)/2. A good formula to remember. 
Solutions: x = Population of City X in 2015 and y = Population of City Y in 2010
Solution: Using Pythagorean theorem:
Solutions: Let y = the profit that the organizer makes.
