The answer would be:
C=12x-1
x being the amount of hours Carey is working.
c being the amount she is getting paid.
The reason why it is 12 is because Anderson is only getting paid $6 per hour, which is half minus 1 per hour Carey is getting paid.
So, by doubling the amount of what Anderson is getting paid minus 1, multiplied by the amount of hours she is working, you should get the correct answer.