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 the correct choice from the following.
A) 14	B) 15	C) 16	D) 17	E) 18

Rationale: "let x be the number of years . 4 x > 100 - 3 x 7 x > 100 x > 14 + 2 / 7 the answer is b ."
Answer: B