The following items appeared in the Investing Activities section of Apple Computer's 2010 statement of cash flows. (All amounts are in millions of dollars.)
2010 2009 2008
Purchases of marketable securities...................$(57,793).......$(46,724).......$(22,965)
Proceeds from maturities of marketable securities....24,930...........19,790..........11,804
Proceeds from sales of marketable securities..........21,788...........10,888............4,439
Purchases of other long-term investments..................(18)............(101).............(38)
Required
1. What amount did Apple spend in 2010 to purchase marketable securities? How does this amount compare to the amounts spent in the two prior years?
2. What amount did Apple receive from marketable securities that matured in 2010? How does this amount compare to the amounts received in the two prior years?
3. The third line in the preceding excerpt reports proceeds from sales, rather than maturities, of marketable securities. Why would certain types of marketable securities mature while others would be sold?