How would you challenge the slow learner and the advanced learner within the same class?

Design tasks that they can work on together collaboratively.

You should also arrange for remedial classes for those students who are not bright enough so that they might catch up with the intelligent chaps in class by the end of the term. You will require a lot of patience to deal with dim witted students.

In my teaching practise I never had such a mixed class, I either had a slower and weaker students, or  stronger and better ones. Motivation was the same - to achieve knolwedge and master it