Here is the answer to the question above. If the value of an airplane is depreciating at a rate of 7% per year, and in the year 2004, it was worth 51.5 million, here is the value of the airplane in 2013.
2005 : 47, 895, 000
2006 : 44, 542, 350
2007 : 41, 424, 385.5
2008 : 38, 524, 678.5
2009 : 35, 827, 951
2010 : 33, 319, 994.4
2011 : 30, 987, 594.8
2012 : 28, 818, 463.2
2013 : 26, 801, 170.8
So the value of the airplane in 2013 is $26, 801, 170.8.
Hope this helps.