Natasha from St Aldhelms School sent in this solution:

Firstly she asked herself how many miles Jacque had walked:

3 miles per hour x 8 hours = 24 miles from home

24 miles, 9 per hour = 2 hours 40 mins as the time he took to cycle

Jacque walked for 8 hours and he rode for 2 hours 40 mins so:

8 hours - 2hours 40mins = 5 hours 20 mins longer walking