One half of a number means that you take a number and then divide it by 2. Decreasing it by 16 means subtracting 16 from it. Therefore, the answer to this question is 1/2n - 16. The key words here are half and decreased.
(1/2n)-16 One half of a number means that you take a number, <em />"n," and then halve it (divide it by 2 or multiply it by one half). Decreasing it by 16 means subtracting 16 from it