I typed in the correct answer to the problem, but the website wouldn't accept. I pressed hint until it gave me the correct answer, and I had gotten the correct answer but it wouldn't submit.
Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.22 (KHTML, like Gecko) Chrome/25.0.1364.152 Safari/537.22
MathJax is loaded, ready, queue length: 0
User hash: 1449857303
Thank you for reporting a problem with this exercise. This issue has been open for over a week and unfortunately no one has had a chance to look at it yet.
We get close to 100 new issues reported each day, many of which are not real bugs, but simply students having difficulty with the math. Unfortunately this means that even with the assistance of our awesome volunteers, we can't always go through and address each issue individually. Consequently, this issue is being automatically closed.
If you're still experiencing a problem, please report it again! We always keep an eye on the ratio of users reporting a problem to users successfully using an exercise, so reporting a problem--even if we can't individually address it--really helps.