Answer:
heavier carton weights 6 pounds more than the lighter carton.
Step-by-step explanation:
Given:
Weigh of Carton 1 = 
Weigh of carton 2 = 
Average weight of cartons is = 10 pounds.
We need to find the heavier carton weights how many more pounds than the lighter carton.
Solution:
We know that;
Average weight of cartons is equal to sum of weighs of carton 1 and carton 2 and then divided by 2.
framing in equation form we get;

Now multiplying both side by
we get;

Adding both side by 1 we get;

Now weigh of Carton 1 = 
Weigh of Carton 2 = 
now we can say that heavier carton is carton 1 and lighter carton is Carton 2.
We need to find the difference between carton 1 and carton 2.
Difference = 
Hence heavier carton weights 6 pounds more than the lighter carton.