Answer:
Peter hit 12 home runs and alice hit 6 home runs
Explanation:
this is right because if Peter hit 6 and then he hit twice the amount that would bring his total to 12 due to 6 x 2 = 12 and if together they hit 18 home runs that would mean you want to subtract the total from Peter's and that would be explained as 18-12=6 and the 6 left over would leave you with alice number of home runs. Hope this helps :)