Buzz has three kite strings averaging 6600 feet in length. None is less than 6200 feet long. How long can the longest be?

The three strings together total 3 x 6600 = 19,800 feet in length. In the extreme case that two of them are only 6200 feet long, then the third one is 19,800 – 2(6200) = 7400 feet long.