Someone asked a guy about something and I think the answer would be true or false, or yes or no, but the guy said, "That's track." What does it mean?
What they most likely said was, "That tracks," which means they agree, or think that what was said is consistent with what they think or believe to be true, that the statement makes sense, or the statement seems logical to them. It can be interpreted as "true" or "yes".
Person 1: When you stand in the shade, it feels cooler because the Sun is not shining directly on you?
Person 2: That tracks.
The usage may not be common across all English-speaking regions but it is an expression that I am familiar with from Australia.
An example of how "that tracks" can be used can also be found at http://context.reverso.net/uebersetzung/englisch-deutsch/That+tracks
That tracks with what I'm seeing here - buses, subways, trains, all running like clockwork.
Das deckt sich mit dem, was ich sehe... Busse, U-Bahnen, Züge, alles läuft wie ein Uhrwerk.
The origin has also been asked on reddit: Does anyone know the origin of the phrase "That tracks?"