It will be $2.50 for each pound of walnuts, and it will be $1 for each pound of chocolate chips.
I know this hold true because when we multiply $2.50 by 2, we get $5, and add that to the other $5 from the chocolate chips and we will get $10. We can also multiply $2.50 by 8 and add $3 from chocolate chips to get $20 + $3, or $23.