Помогите , пожалуйста, решить номер из олимпиады.
Choose the correct preposition in these sentences.

1. I often go abroad in business/on business.
2. It took a long time but in the end/at the end we got there
3. Who knows if it’s true, but that’s what I heard on the radio/in the radio
4. We had a vote in the end/at the end of the meeting.
5. We’ve been in business/on business now for fifteen years.