One pound is equal to 16 ounces. so to do this you would need to multiply 5 by 16 to get 80 ounces total. Then you would subtract the 12 from the 80 since she gave it away and it isn't included in the bags that she is giving out.this leaves you with 68 ounces. Finally, you would divide 68 by 4 to get 17. She made a total of 17 bags of trail mix.