Since he started with 12 puppets, that means that he made 48 puppets in 8 days. Hence he makes 6 puppets per day.
Let x be the number of days passed and p the number of puppets then we have that he makes:
[tex]6x[/tex]in x days. To this we have to add the initial number of puppets, therefore the total number of puppets is given as:
[tex]p=6x+12[/tex]