Economic risk is a nebulous term with a variety of definitions. In a nutshell, it is the risk that an endeavor will be economically unsustainable, for a variety of reasons ranging from a change in economic trends to fraudulent activities which ruin the outcome of the project.
The summer solstice arrives Sunday June 21. Those of us in the Northern Hemisphere know it as the longest day of the year.
From this graph we can see that the longest day of the year occurs between day 170 and day 180. By checking the values of DAYLIGHT for x between 170 and 180, we find that the longest day occurs on day x=173, or June 22, and that that day is 15 hours and 32 seconds long.