This is the 5856th most frequent Japanese word.
ふん
"ふん" means "excrement" or "feces" in English, and can also express disdain as an interjection ("hmph").
In this context, 'ふん' is an onomatopoeia expressing a feeling of disdain or disapproval.
彼は時計を見て「ふん」と言いました。
He looked at the clock and said 'Hmph.'
Here, 'ふん' is a counter representing minutes in time measurements.
この問題は15ふんで解けます。
This problem can be solved in 15 minutes.
Similar to the previous example, 'ふん' is used to count minutes, showing duration in this instance.