Using algebra:
If Marco has 6 as many stamps as ben,
You can let Ben = x
Then Marco would be 6x
A ll of the stamps combined would be 7x, which is equal to 42
Therefore: 7x = 42 and x = 6
Once you know x you know that Ben is 6 (x) and that Marco is 36 (6x)
These are the 2 amounts, you can also re-check by adding them (42) and making sure they add up to the total (42).
With the two amounts of both Ben and Marco, you can simplay find the difference by subtracting Marcos amount with Bens, (36-6).
This is equal to 30, therefore Marco has 30 more stamps than Ben.
