More information is required to answer the question correctly.
Answer:
9.3 hours
Step-by-step explanation:
Given

Required
Hours of sunlight on Feb 21, 2013
First, calculate the number of days from Jan 1, 2013 to Feb 21, 2013

So:

So, we have:







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<em> --- approximated</em>
Answer: x=8
Step-by-step explanation: Solve for x by simplifying both sides of the equation, then isolating the variable.
Hope this helps you out.