The ordinal number following thirty

तीस पहला

English Usage: She finished in thirtieth place in the race.

Hindi Usage: वह दौड़ में तीस पहले स्थान पर समाप्त हुई।

Describing something that is one of thirty in a sequence

तीसरा

English Usage: This is the thirty-first chapter of the book.

Hindi Usage: यह किताब का तीसरा अध्याय है।