Answer:
The problem in the following snippet is that the function "cost" returns the void and it cannot used as the expression in the print statement
Explanation:
public class Test 
{ 
     public static void main(String[] args) 
     { 
           System.out.println(cost(10, 4));
      } 
      public static void cost(int price, int reps) 
      { 
            for (int i = 0; i < reps; i++)  
            { 
                    System.out.print(price);                 
            }   
      } 
}
Output:
Main.java:4: error: 'void' type not allowed here
         System.out.println(cost(10, 4));
                                ^
1 error
In the following code the void type is not allowed in the function "cost".