Welcome to the forums, ablinsag.
In future posts. . .
1. Please ask a question in a complete sentence in standard English (as far as you are able). Like this:
'What does the idiom "coming out in flying colors" mean?'
2. Please give your thread a title which includes the word or phrased being asked about – such as 'coming out in flying colors'.
3. Please note that we have a forum dedicated to idioms. Click HERE to find it.
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To answer your question, the idiom is not 'in...' but 'with flying colo(u)rs'.
(From our own list of idioms)With flying colours (colors)If you pass something with flying colours (colors), you pass easily, with a very high mark or grade.