Russian Elementary Math Problem.

[Frisco]

This Math is difficult for many people including myself.

I found the question here: http://www.city-data.com/forum/automotive/1350955-math-problem-russian-elementary-school-students.html

 

[iJohnHenry]

What happens when one end is 'above 60º' latitude, like Barrow, Alaska??

The sun sets on November 18 or 19, and it remains below the horizon for about 65 days. This creates a polar night that lasts until the sun rises again around January 22 or January 23. During the first half of the polar night, there is a decreasing amount of twilight each day, and on the winter solstice (around December 21 or December 22), civil twilight in Barrow lasts for a mere 3 hours.[11][13]