Peter hit twice the diffrence of the number of home runs Alice hit and 6.
Altogether, they hit 18 home runs.
Let x represent the number of home runs Alice hit. Peter 2%28x-6%29
2(x-6) + x = 18
3x = 30
x = 10, the number of home runs Alice hit. Peter: 8 2%28x-6%29
And:
10 + 8 = 18 CHECKS!
Each player has 10+8=18 home runs in this sessin