Answer
The size of decrease in 2010 will be 176 pairs.
The estimated total decrease for the years 2007 through 2010 is 740 pairs.
Work Step by Step
As the size of the decrease in owl population for a given year is estimated to be 200 - 6n pairs,
For 2007 as year 1, the size of decrease is 200-6x1 = 194 pairs
For 2008 as year 2, the size of decrease will be 200-6x2 = 188 pairs
For 2009 as year 3, the size of decrease will be 200-6x3 = 182 pairs
For 2010 as year 4, the size of decrease will be 200-6x4= 176 pairs
And, the estimated total decrease for the years 2007 through 2010 will be 194 + 188 + 182 + 176 pairs = 740 pairs
