Here. The comment says it was closed for being unclear.
Two things:
To me it is perfectly clear. Surely, it could have been worded better, and perhaps added a bit of extra calculation, but the answer is overall correct.
If do not agree, then instead of delete, why not to ask for clarification rather than to close it? Seem a rather harsh decision. Even a downvote would have been better. If we apply such strict policy, a lot of answers here would be already deleted.