Answer:
There were 7 small boxes and 14 large boxes shipped.
Explanation:
This problem may be solved by a system of equations:
I am going to say that:
x is the number of small boxes used
y is the number of large boxes used
There were twice as many large boxes shipped as small boxes shipped
This means that

Each small box of paper weighs 45 pounds and each large box of paper weighs 80 pounds. The total weight of all boxes was 1435 pounds.
This means that

So we have to solve the following system:






There were 7 small boxes and 14 large boxes shipped.