Given that in one baseball season, Peter (p) hit twice the number of homeruns that Mark (m) hit. This can be interpreted algebraically as shown below:
Also, given that together they hit 18 homeruns. This can be interpreted as shown below:
Substitute p = 2m in the total home runs to know the home runs each person hit as shown below:
Substitute for m in p= 2m to p as shown below:
Hence, Peter hits 12 homeruns and Mark hits 6 homeruns