Hamburgers Sold During March 2010 and Total Until March 31st 2010

McDonald's announced in their first quarter Earnings call that their systemwide sales growth % excluding foreign currency fluctuations was 8%. Now, in order to calculate the total hamburger sales in March 2010 I need to calculate the systemwide sales growth % for march 2010, we know that January= 4.3% and February= 6.4%, so then with a simple algebra we can figure our March (4.3 + 6.4 + X)/3 = 8.0 therefore X=13.2% for March

Now I take estimated March 2009 sales 1,188,500,041 and multiply times (1 + 13.2%) to get 1,345,682,046 hamuburger sales in March 2010.

Now I just add that to number of total hamburgers sold as of February 28th 2010 244,013,505,763 + 1,345,682,046 = 245,359,187,809 total sold until March 31st 2010