1. 17

2. 729 (cubes of consecutive odd numbers: 729 = 93)

3. 27 (Given 3 and 7 as the first two numbers in the sequence, each succeeding number is the sum of the two previous numbers in the sequence)

4. 12 people

5. 23

6. He will never do it. In fact by these rules he is limited to less than 20 metres in total.

7. 78

8. The house numbers

9. 13 people

10. (In order) 10, 15, 9, 20, 12