In order to solve this problem, the approach should be formulating equations such that they form a system of linear equations. Let's start by assigning variables. Let x be the number of homeruns made by Peter, and y be the number of homeruns made by Alice. Therefore,
x = 2(y - 6)
This is the equation for the relationship between Peter's and Alice's hits. The second equation would be the sum of their hits:
x + y = 18
These are the two independent equations in order to solve the two unknowns, x and y. Substituting the first equation into the second equation,
2(y - 6) + y = 18
2y - 12 + y = 18
3y = 18 + 12
3y = 30
y = 10
Using y=10 to the first equation:
x = 2(10 - 6)
x = 8
Therefore, Peter made 8 homeruns, while Alice made 10 homeruns for a total of 18.