Simon mixes dried fruits and nuts to make a trail mix that he sells at the farmer's market. The dried fruits cost $6 per pound. The nuts cost $2 per pound. It costs Simon $40 to make 12 pounds of trail mix.
Which system of equations can be used to find the number of pounds, x, of dried fruits and the number of pounds, y, of nuts that Simon used
to make 12 pounds of trail mix?