At a contest with 3,500 participants, 1/2 of the people are aged 18 to 22. Next year, the number of people aged 18 to 22 will increase by 1/7. After this change, what percentage of the total 3,500 people will the 18- to 22-year-olds represent? Select: A) 33 % B) 40 % C) 55 % D) 57.14 % E) 66.14 %

Rationale: "i just wanted to mention a couple of things here : * this is a pure ratio question ; the number 3,500 is completely irrelevant , and you can ignore it if you like . when we increase something by 1 / 7 , we are multiplying it by 1 + 1 / 7 = 8 / 7 , so the answer here must be ( 1 / 2 ) * ( 8 / 7 ) = 4 / 7 = 57.14 % . answer : d"
Answer: D