A certain airline's fleet consisted of 100 type A planes at the beginning of 1980. At the end of each year, starting with 1980, the airline retired 3 of the TYPE A planes and acquired 4 new type B plans. How many years did it take before the number of type A planes left in the airline's fleet was less than 50 percent of the fleet?  Choose one:
A) 14  B) 15  C) 16  D) 17  E) 18
Let x be the number of years.   4x &gt; 100 - 3x   7x &gt; 100   x &gt; 14 + 2/7   The answer is 15.
<result>B</result>
A certain airline's fleet consisted of 100 type A planes at the beginning of 1980. At the end of each year, starting with 1980, the airline retired 3 of the TYPE A planes and acquired 4 new type B plans. How many years did it take before the number of type A planes left in the airline's fleet was less than 50 percent of the fleet?