An aircraft company has 20 planes in its fleet. Every year it retires 5 of its planes and replaces then with 6 newer planes. How many years will it take the company, starting from 2010, to reduce the number of it s old planes to less than half of its fleet?
Pick
A) 2	B) 1	C) 3	D) 4	E) 5
Total fleet--20   End of year 2010 -- (retires 5 and buys 6) total fleet--21(15 old 6 new).   End of year 2011 -- (retires 5 and buys 6) total fleet--22(10 old 12 new).   End of year 2012 -- (retires 5 and buys 6) total fleet--23(5 old 18 new).   2nswer is 2--after 2 years the company has a total of 22 planes (10 old 12 new).
<result>A</result>
An aircraft company has 20 planes in its fleet. Every year it retires 5 of its planes and replaces then with 6 newer planes. How many years will it take the company, starting from 2010, to reduce the number of it s old planes to less than half of its fleet?