I know this has been answered, but i still want to explain it, if you wanted help
2n ≥ 15
work:
extract the elements of the problem.
Twice a number (we will use 2n because we don't know the number)
at least 15 (≥ 15 make sure you have the line underneath the equality symbol! "at least 15" means it ca also be 15!)
put them together.
2n ≥ 15
hope this helped! :D
