Explanation:
As the like charges repel and opposite charges attract each other. When we bring the test positive charge near to the positive charge then it will move away. If one want to score a goal then he/she has to bring the positive charge behind the test charge, repulsion will cause the test charge to move away from the positive charge and it will go into the goal.
As far as difficult levels are concerned you should put the positive charges outside the path which you want your test charge to take. Hope you understand it.
